I am not sure whether you refer to delta S (change in entropy) or entropy itself. So I'll answer for both.

For S (entropy), which is defined by the function S=kln(omega), where k is Boltzmann's constant and omega is the number of microstates corresponding to a given state, the answer is no. Why? Omega (the number of microstates possible for a certain state) can never be smaller than one. Since Boltzmann's constant is a positive number and ln(omega) will always be greater or equal to zero, entropy will never be negative.

However, when calculating delta S (change in entropy in a thermodynamic process), yes entropy can be negative. Remember entropy is essentially the state of disorder of a system since (on a macroscopic level) the natural progression of the world is from order to disorder. (For example, there are more ways to have a messy room than to have an impeccable, neat room). For the change in entropy to be negative just think of it in terms of the room analogy: initially, it was messy, but then it got neater. The state of disorder of things was lessened. Applying this to a chemistry example:

CO 2 (g)--> CO 2 (s)

An element/compound in a gaseous state always has a greater state of entropy (gaseous molecules are more free to move). However, an element/compound in a solid state has a smaller state of entropy because molecules in a solid are less free to move. Smaller state of entropy - greater state of entropy=negative entropy

3-letter words

sty

4-letter words

arty, city, doty, duty, mity, paty, pity

5-letter words

amity, aunty, banty, batty, bawty, bitty, booty, borty, busty, butty, canty, catty, cutty, deity, dicty, dirty, ditty, dorty, dotty, dusty, empty, fatty, fifty, fluty, footy, forty, fusty, gouty, gusty, gutty, hasty, hefty, hooty, janty, jetty, jolty, jotty, jutty, kilty, kitty, laity, lefty, linty, lofty, lusty, malty, meaty, milty, minty, misty, musty, nasty, natty, netty, nifty, nitty, nutty, panty, party, pasty, patty, peaty, petty, piety, platy, potty, pouty, punty, putty, ratty, rooty, runty, rusty, rutty, salty, silty, sixty, slaty, softy, sooty, suety, tarty, tasty, tatty, tenty, testy, titty, tufty, tutty, unity, vasty, warty, whity, witty, zesty, zloty

6-letter words

acuity, agouty, beauty, blasty, blotty, bounty, bratty, cavity, chanty, chatty, cherty, chesty, chitty, clotty, comity, county, crafty, crusty, dainty, deputy, dimity, drafty, drifty, eighty, enmity, entity, equity, faulty, fealty, feisty, ferity, fixity, flinty, flirty, floaty, fretty, frosty, fruity, gaiety, gayety, ghosty, gleety, gnatty, gritty, grotty, grouty, guilty, hearty, jaunty, knotty, laxity, lealty, lenity, levity, mighty, moiety, nicety, nighty, ninety, nudity, oddity, painty, parity, pigsty, plenty, plotty, pointy, polity, pretty, purity, rarity, realty, righty, safety, sanity, scanty, scatty, shanty, shelty, shifty, shirty, shorty, slanty, sleety, smarty, smutty, snooty, snotty, snouty, sporty, spotty, surety, swarty, sweaty, thirty, toasty, treaty, trouty, trusty, twenty, twisty, ubiety, uppity, vanity, vaulty, vaunty, verity, wristy, yeasty

7-letter words

ability, acidity, agility, amenity, aminity, amnesty, anality, anility, annuity, anxiety, aplenty, aridity, avidity, bedirty, bheesty, biggety, biggity, biparty, blighty, brevity, carroty, charity, christy, clarity, crudity, cruelty, dacoity, dakoity, density, dignity, doughty, duality, dubiety, dynasty, edacity, faculty, falsity, fatuity, ferrety, fidgety, flaunty, flighty, frailty, frowsty, furmety, furmity, gadgety, gargety, gravity, haughty, honesty, impiety, inanity, jollity, liberty, loyalty, maggoty, majesty, modesty, naivety, naughty, nimiety, novelty, nuggety, nullity, obesity, opacity, orality, outpity, ovality, parroty, paucity, paughty, penalty, piosity, poverty, privity, probity, puberty, quality, rabbity, rackety, raucity, reality, rickety, royalty, russety, satiety, seventy, society, squatty, squinty, suavity, tensity, tenuity, thirsty, thrifty, throaty, trinity, unhasty, utility, vacuity, variety, varsity, vastity, velvety, viduity, weighty

8-letter words

acerbity, acridity, activity, affinity, alacrity, algidity, almighty, anticity, asperity, atrocity, audacity, axiality, banality, basicity, bifidity, bovinity, caducity, calamity, caninity, capacity, casualty, celerity, chastity, circuity, civility, conicity, cubicity, cupidity, debility, disunity, divinity, docility, draughty, droughty, enormity, entirety, entreaty, epinasty, epizooty, equality, equinity, eternity, exiguity, facility, fatality, felicity, felinity, feminity, feracity, ferocity, fidelity, finality, fluidity, fortuity, fromenty, frumenty, fugacity, furmenty, futility, futurity, gelidity, gratuity, guaranty, gulosity, helicity, heredity, hilarity, humanity, humidity, humility, ideality, identity, idoneity, immunity, imparity, impunity, impurity, inequity, infinity, iniquity, insanity, inverity, ionicity, jejunity, jocosity, jovialty, lability, lanosity, latinity, legality, legerity, lividity, locality, lucidity, majority, maturity, mesnalty, minacity, minority, mobility, modality, molality, molarity, morality, moronity, morosity, motility, motivity, mucidity, mucosity, nasality, natality, nativity, nihility, nobility, nodality, nodosity, nonempty, nonfatty, nonparty, nubility, obtusity, otiosity, penality, peripety, pilosity, polarity, porosity, priority, property, quantity, quiddity, rabidity, ramosity, rapacity, rapidity, regality, rigidity, rimosity, rugosity, rurality, sacristy, sagacity, salacity, salinity, sanctity, sapidity, scarcity, security, sedulity, senility, serenity, serosity, severity, snippety, sobriety, sodality, solidity, sonority, sorority, sovranty, sparsity, subtilty, subtlety, temerity, tenacity, tepidity, thickety, timidity, tonality, tonicity, toplofty, torosity, totality, touristy, toxicity, travesty, triunity, tumidity, ubiquity, unpretty, unsafety, untrusty, urbanity, vagility, validity, vapidity, velleity, velocity, venality, venosity, veracity, vicinity, vinosity, viridity, virility, vitality, vivacity, vocality, voracity, warranty, zygosity

9-letter words

absurdity, acclivity, actuality, adiposity, admiralty, adversity, ambiguity, amorality, animality, animosity, anonymity, antiparty, antiquity, apriority, arability, asininity, assiduity, atonality, austerity, authority, barbarity, benignity, biosafety, brutality, callosity, captivity, carnality, causality, celebrity, certainty, champerty, chirality, chocolaty, clonicity, coevality, commodity, community, concavity, congruity, contrasty, convexity, credulity, crotchety, curiosity, cyclicity, declivity, deformity, depravity, dexterity, disparity, diversity, ductility, duplicity, edibility, emotivity, erosivity, ethnicity, extensity, extrality, extremity, facticity, fecundity, fertility, festivity, feudality, fissility, floridity, formality, fragility, frigidity, frivolity, frugality, garrulity, geniality, gentility, gibbosity, gracility, gravidity, hideosity, hostility, hybridity, iconicity, immensity, immodesty, inability, indemnity, indignity, inebriety, infirmity, ingenuity, integrity, intensity, intercity, inutility, irreality, jocundity, joviality, lethality, liability, limpidity, lineality, linearity, liquidity, longevity, loquacity, lubricity, malignity, maternity, mayoralty, mendacity, mendicity, mentality, modernity, morbidity, mortality, multicity, mundanity, mutuality, necessity, nervosity, noncounty, nonentity, normality, notoriety, obliquity, obscenity, obscurity, overhasty, passivity, paternity, pederasty, placidity, planarity, plurality, pomposity, posterity, precocity, predacity, primality, profanity, prolixity, propriety, proximity, publicity, puerility, pugnacity, putridity, rancidity, rascality, rotundity, rusticity, salubrity, sectility, seniority, sequacity, sergeanty, serjeanty, servility, severalty, sexuality, sincerity, sinuosity, sociality, solemnity, specialty, spinosity, stability, sterility, stolidity, stupidity, suability, subcounty, sublimity, supercity, tactility, tensility, torpidity, torridity, turbidity, turgidity, unanimity, unclarity, unreality, unthrifty, usability, verbosity, viability, villosity, virginity, viscidity, viscosity, viscounty, vorticity, vulgarity

10-letter words

abstrusity, actability, adaptivity, additivity, affability, alkalinity, amiability, angularity, aquilinity, asexuality, audibility, bestiality, bimodality, bipedality, bipolarity, canonicity, capability, causticity, centrality, centricity, chlorinity, chronicity, coequality, coercivity, comicality, commonalty, complexity, complicity, concinnity, conformity, contiguity, continuity, cordiality, corporeity, creativity, curability, cutability, difficulty, disability, dishonesty, disloyalty, disutility, durability, dyeability, efficacity, elasticity, emissivity, endemicity, equability, equanimity, erectility, ergodicity, ethicality, factuality, femininity, flaccidity, fraternity, friability, frontality, fusibility, generality, generosity, ignobility, illegality, imbecility, immaturity, immobility, immorality, impudicity, inactivity, incapacity, incivility, indocility, inequality, infelicity, infidelity, inhumanity, insecurity, insipidity, insobriety, insularity, interparty, invalidity, jocularity, juvenility, legibility, lexicality, liberality, likability, literality, livability, logicality, lovability, luminosity, mediocrity, modularity, movability, muliebrity, multiparty, musicality, mutability, nebulosity, negativity, neutrality, nonfaculty, nonutility, notability, nuptiality, optimality, organicity, orotundity, osmolality, osmolarity, overmighty, partiality, pernickety, perpetuity, perplexity, personalty, perversity, plasticity, pliability, popularity, positivity, potability, preciosity, prepuberty, proclivity, profundity, propensity, prosperity, quaternity, reactivity, regularity, relativity, risibility, salability, sanguinity, scurrility, secularity, seismicity, seminudity, sensuality, sensuosity, sewability, shrievalty, similarity, simplicity, solidarity, solubility, spasticity, spatiality, speciality, speciosity, sphericity, subsociety, subvariety, suzerainty, synonymity, tenability, topicality, tortuosity, triplicity, triviality, tuberosity, tunability, unchastity, uniformity, university, unmorality, varicosity, virtuality, virtuosity, visibility, viviparity, volatility, volubility

11-letter words

abnormality, adorability, affectivity, amenability, amicability, analyticity, angioplasty, antianxiety, anticruelty, antigravity, antiobesity, antipoverty, aromaticity, bankability, bearability, bellicosity, biconcavity, biconvexity, biddability, bioactivity, bisexuality, bloodguilty, capillarity, cardinality, castability, catholicity, cellularity, circularity, coilability, colinearity, commonality, communality, conjugality, conspicuity, contrariety, coplanarity, corporality, credibility, criminality, criticality, culpability, cyclicality, deniability, diaphaneity, diffusivity, directivity, disquantity, domesticity, drapability, drivability, ecumenicity, educability, effectivity, electricity, eligibility, ellipticity, epidemicity, erasability, erodibility, ethereality, eventuality, exclusivity, exemplarity, expansivity, exteriority, externality, fallibility, familiarity, farcicality, feasibility, fishability, flexibility, formability, fungibility, fussbudgety, grandiosity, granularity, gullibility, historicity, homogeneity, hospitality, hyperacuity, illiquidity, immortality, impassivity, impetuosity, importunity, impropriety, impulsivity, incommodity, incongruity, incredulity, incuriosity, infantility, infectivity, inferiority, infertility, informality, insalubrity, insincerity, instability, integrality, intercounty, interiority, internality, intrepidity, inviability, isotonicity, liveability, longanimity, magnanimity, mailability, marginality, masculinity, materiality, meltability, miscibility, monstrosity, moribundity, multicounty, muscularity, nationality, nonidentity, nonminority, nonmotility, nonvalidity, notionality, objectivity, openability, operability, opportunity, optionality, oracularity, originality, osteoplasty, ototoxicity, overanxiety, packability, palpability, parfocality, partibility, peculiarity, pepperminty, periodicity, persnickety, personality, perspicuity, pertinacity, physicality, placability, playability, portability, possibility, postpuberty, prematurity, primitivity, probability, prodigality, prolificity, promiscuity, propinquity, punctuality, quotability, rationality, readability, receptivity, reciprocity, reflexivity, reliability, religiosity, rentability, resistivity, retentivity, reusability, rhinoplasty, rhythmicity, roadability, rubicundity, schistosity, seasonality, selectivity, semiaridity, sensibility, sensitivity, serendipity, singularity, sociability, solvability, sorbability, sovereignty, specificity, specularity, spiritualty, spontaneity, strenuosity, suitability, summability, superfluity, superiority, syllabicity, taciturnity, tangibility, temporality, testability, tranquility, triaxiality, uncertainty, variability, vascularity, vendibility, versatility, verticality, viceroyalty, violability, volcanicity, vulcanicity, washability, wearability, wettability, workability

12-letter words

absorptivity, adaptability, admirability, adoptability, advisability, aggressivity, agreeability, alienability, alterability, anelasticity, antigenicity, aperiodicity, apostolicity, assumability, authenticity, autoimmunity, automaticity, automobility, availability, avascularity, avuncularity, binocularity, biodiversity, bloodthirsty, brushability, chromaticity, churchianity, classicality, cleanability, collectivity, collegiality, collinearity, compulsivity, conductivity, congeniality, connectivity, connubiality, conviviality, coprosperity, corporeality, countability, crossability, cytotoxicity, decidability, desirability, detonability, dilatability, divisibility, drapeability, drillability, drinkability, driveability, eccentricity, effectuality, electability, emotionality, ephemerality, equitability, equivocality, essentiality, excitability, exhaustivity, expressivity, fatigability, fictionality, flammability, forgeability, frangibility, habitability, hatchability, heritability, heterogamety, homozygosity, honorability, hyperacidity, hypotonicity, ignitability, illegibility, illiberality, illogicality, immovability, immutability, impartiality, imputability, inaudibility, incapability, inconcinnity, inconformity, incorporeity, indelibility, inducibility, ineffability, inelasticity, infusibility, insolubility, insurability, interfaculty, intersociety, invisibility, irascibility, irregularity, irritability, keratoplasty, lachrymosity, leachability, lognormality, lysogenicity, malleability, memorability, meticulosity, microgravity, mitogenicity, modulability, monotonicity, multiformity, multiplicity, multiversity, municipality, mutagenicity, navigability, noncelebrity, noncommunity, nonlinearity, nonnecessity, oncogenicity, opposability, overactivity, overcapacity, overmaturity, palatability, pansexuality, perceptivity, perfectivity, permeability, permittivity, perspicacity, plausibility, pneumaticity, polytonality, posteriority, potentiality, practicality, pregnability, prehensility, principality, printability, productivity, pseudonymity, pyrogenicity, quizzicality, reducibility, reflectivity, refractivity, regressivity, removability, renewability, reputability, retractility, saccharinity, scrupulosity, sempiternity, separability, severability, shareability, simultaneity, spirituality, stainability, subcommunity, subjectivity, subnormality, subsidiarity, subspecialty, supergravity, superquality, susceptivity, synchroneity, technicality, tolerability, toxigenicity, traceability, tractability, trainability, tranquillity, transitivity, treatability, trustability, unconformity, ungenerosity, unisexuality, universality, unpopularity, untenability, vasoactivity, venerability, veridicality, vesicularity, voluminosity, whimsicality

13-letter words

absorbability, acceptability, accessibility, adjustability, admissibility, affectability, affordability, allergenicity, ambidexterity, ambisexuality, analyzability, anfractuosity, antiauthority, antifertility, antiobscenity, antisexuality, appealability, applicability, artificiality, assignability, associativity, attainability, believability, breathability, changeability, clandestinity, coagulability, codifiability, collaterality, colloquiality, commerciality, commutativity, comparability, compatibility, computability, concentricity, conceptuality, confraternity, connaturality, consanguinity, contractility, corrigibility, creditability, crystallinity, cultivability, damageability, deductibility, defeasibility, defensibility, delectability, dependability, destructivity, detachability, detectability, deterrability, digestibility, disconformity, discontinuity, disposability, dissimilarity, egocentricity, employability, enumerability, excludability, exothermicity, expandability, expansibility, expendability, exportability, extendability, extensibility, extrudability, filterability, formidability, functionality, germinability, heterogeneity, homosexuality, horizontality, hyperactivity, hypermobility, hypersalinity, hypertonicity, hypervelocity, immateriality, immiscibility, impalpability, impassability, impassibility, impeccability, impecuniosity, impersonality, implacability, impossibility, improbability, improvability, incredibility, individuality, ineducability, ineligibility, inevitability, inexorability, infallibility, infeasibility, inflexibility, inhomogeneity, inhospitality, insatiability, insensibility, insensitivity, insociability, instantaneity, intangibility, integrability, invariability, invincibility, inviolability, irrationality, machinability, manageability, marketability, measurability, mensurability, metastability, microporosity, microtonality, modifiability, monumentality, multipolarity, negligibility, negotiability, neurotoxicity, nonadditivity, nonconformity, noncreativity, nonuniformity, nonuniversity, observability, obtainability, orthogonality, overdiversity, overingenuity, overintensity, overstability, paranormality, parasexuality, particularity, patentability, pathogenicity, penetrability, perdurability, perishability, phototoxicity, phytotoxicity, preferability, preuniversity, profitability, progressivity, promotability, provinciality, punishability, pusillanimity, quadruplicity, radioactivity, reasonability, recallability, reeligibility, reformability, refundability, remediability, repairability, repeatability, replicability, resectability, resistibility, retroactivity, reversibility, sacrosanctity, saprogenicity, sinterability, solderability, spreadability, squeezability, superactivity, superfluidity, superhumanity, supermajority, supersubtlety, survivability, synchronicity, theatricality, triangularity, ultravirility, underactivity, unfamiliarity, unknowability, unpunctuality, unreliability, unsociability, unsuitability, unworkability, upgradability, verifiability, vulnerability

14-letter words

accountability, addressability, aeroelasticity, antiuniversity, assimilability, bioelectricity, blepharoplasty, collapsibility, combustibility, compensability, conceivability, conditionality, conductibility, confirmability, convertibility, corruptibility, curvilinearity, deliverability, denumerability, dimensionality, directionality, disciplinarity, dispensability, dissociability, distensibility, distributivity, enforceability, exceptionality, exhaustibility, extemporaneity, extensionality, extractability, falsifiability, fantasticality, fashionability, fissionability, foreseeability, goitrogenicity, grammaticality, hepatotoxicity, heterozygosity, hydrophilicity, hydrophobicity, hygroscopicity, hypersexuality, hyperviscosity, illimitability, immunogenicity, impermeability, implausibility, impracticality, impregnability, impressibility, inadvisability, inalienability, inalterability, inauthenticity, indefinability, indivisibility, indomitability, indubitability, ineffectuality, ineluctability, inflammability, infrangibility, inheritability, inscrutability, inseparability, intensionality, intentionality, intercommunity, interfertility, intersexuality, intersterility, intolerability, intractability, intransitivity, irreducibility, irrefutability, irremovability, irrevocability, justiciability, justifiability, localizability, machineability, manipulability, nephrotoxicity, nonobjectivity, overgenerosity, paradoxicality, perceptibility, perfectibility, performability, permissibility, pleasurability, polarizability, polydispersity, practicability, predictability, presentability, preservability, preventability, processability, processibility, recoverability, rectangularity, rectifiability, referentiality, refrangibility, repressibility, respectability, responsibility, retrievability, salvageability, sentimentality, seronegativity, seropositivity, serviceability, stretchability, substantiality, suggestibility, superficiality, superintensity, supernormality, supersexuality, supportability, susceptibility, sustainability, teratogenicity, territoriality, theocentricity, thermolability, trafficability, transmissivity, transsexuality, tumorigenicity, unalterability, unavailability, uncongeniality, undecidability, undesirability, unflappability, unpalatability, unthinkability, untouchability, upgradeability, weatherability

15-letter words

agglutinability, antirationality, approachability, bioavailability, carcinogenicity, communicability, complementarity, compressibility, confidentiality, contemporaneity, contemptibility, contractibility, controllability, conventionality, decomposability, demonstrability, destructibility, disreputability, distractibility, dorsiventrality, dorsoventrality, ethnocentricity, exchangeability, heterosexuality, hypermutability, hyperreactivity, hypnotizability, impenetrability, imperishability, imponderability, inaccessibility, inadmissibility, inapplicability, incalculability, incomparability, incompatibility, incorrigibility, indefeasibility, indefectibility, indefensibility, indigestibility, indissolubility, ineffaceability, ineradicability, inexplicability, inextricability, instrumentality, intellectuality, intelligibility, interfraternity, interuniversity, intervisibility, invulnerability, irreformability, irrefragability, irrepealability, irresistibility, irreversibility, maintainability, maneuverability, marriageability, merchantability, microseismicity, monospecificity, monosyllabicity, nonavailability, nonflammability, nucleophilicity, overfamiliarity, oversensitivity, programmability, proportionality, psychosexuality, pyroelectricity, recognizability, reconcilability, rememberability, reproducibility, superplasticity, suppressibility, thermostability, transferability, translatability, unacceptability, unanswerability, unassailability, unchangeability, unemployability, viscoelasticity

16-letter words

biocompatibility, biodegradability, commensurability, companionability, consequentiality, discriminability, electrophilicity, exceptionability, exterritoriality, ferroelectricity, flibbertigibbety, generalizability, homoscedasticity, hydroelectricity, hyperrationality, hypersensitivity, immunoreactivity, impermissibility, imperturbability, impracticability, incombustibility, inconceivability, incontestability, inconvertibility, incorruptibility, indefatigability, indispensability, inexhaustibility, inexpressibility, insubstantiality, insusceptibility, internationality, interoperability, interpretability, irreplaceability, irrepressibility, irresponsibility, irretrievability, knowledgeability, monochromaticity, multicellularity, noncommutativity, noncomparability, nondeductibility, perpendicularity, photosensitivity, piezoelectricity, pronounceability, quasiperiodicity, radiosensitivity, reprehensibility, representativity, semipermeability, stereoregularity, substitutability, supersensitivity, supranationality, thermoplasticity, transmissibility, transportability, triboelectricity, unaccountability, ungrammaticality, unpredictability, unsubstantiality

17-letter words

circumstantiality, comprehensibility, constitutionality, cytopathogenicity, differentiability, disrespectability, electronegativity, hyperemotionality, hyperexcitability, hyperirritability, impressionability, incommunicability, indestructibility, interavailability, intersubjectivity, irreconcilability, irreproachability, irreproducibility, nonenforceability, photoconductivity, stereospecificity, superconductivity, thermoelectricity, thermoperiodicity, transplantability, tridimensionality, unapproachability, unconscionability, uncontrollability, unconventionality, understandability, unidimensionality, unintelligibility, untranslatability

18-letter words

anthropocentricity, distinguishability, histocompatibility, hypercoagulability, incommensurability, inconsequentiality, interchangeability, microcrystallinity

19-letter words

extraterritoriality, hypersusceptibility, incomprehensibility, interconvertibility, multidimensionality, unconstitutionality

20-letter words

indistinguishability

21-letter words

intersubstitutability

22-letter words

intercomprehensibility

1868 words

Words ending in ty with their base words:

unity - base word = unity

majority - base word = major

totality - base word = total

mediocrity - base word = mediocre

deformity - base word = deform

clarity - base word = clear