Take your pick from

coquetting, dallying, flightiness, flippancy, flirting, flummery, folly, fribble, frippery, frivolousness, fun, gaiety, game, giddiness, jest, levity, lightheartedness, lightness, nonsense, play, puerility, shallowness, sport, superficiality, toying, trifling, triviality, volatility, whimsicality, whimsy

Caprice (n.) 1. A sudden, unpredictable change, as of one's mind or the weather. 2. a tendency to change one's mind without apparent or adequate motive; whimsicality; capriciousness: With the caprice of a despotic king, he alternated between kindness and cruelty.

The tone of "Cap and Bells" by W.B. Yeats is a blend of whimsicality and ambiguity. The poem explores themes of love, desire, and the complexities of human relationships through the metaphor of a jester's cap and bells. Yeats uses intricate language and imagery to evoke a sense of playfulness and mystery throughout the poem.

brutality, duality, fatality, finality, formality, frugality, legality, lethality, locality, mentality, modality, morality, mortality, neutrality, normality, tonality, totality, vitality, abnormality, actuality, commonality, criticality, generality, geniality, hospitality, liberality, musicality, nationality, partiality, practicality, sense modality, sensuality, sexuality, touch modality, triviality, unreality, with formality, as a formality, bisexuality, congeniality, dimensionality, impersonality, infant mortality, irrationality, municipality, spirituality, theatricality, universality, without formality, confidentiality, homosexuality, sexual morality, visual modality, auditory modality, genetic abnormality, olfactory modality, congenital abnormality, extraterritoriality

Nationality actuality.

fatality

4 syllables: ethereality immateriality materiality corporeality extraterritoriality incorporeality territoriality axiality bestiality commerciality connubiality impartiality joviality mercuriality partiality provinciality sociality spatiality speciality unreality artificiality superficiality conviviality triviality cordiality primordiality

3 syllables: brutality carnality causality centrality coevality commensality communality dextrality feudality finality (high) fidelity horizontality immortality infidelity integrality lethality magistrality mortality nasality neutrality ovality prodigality rascality spectrality totality universality venality vitality asexuality bisexuality heterosexuality homosexuality intersexuality sexuality unisexuality effectuality ineffectuality intellectuality eventuality confidentiality consequentiality essentiality inconsequentiality potentiality sequentiality tangentiality conventionality extensionality intentionality unconventionality sensuality fundamentality instrumentality mentality sacramentality sentimentality ephemerality generality illiberality liberality literality eternality externality infernality internality nocturnality aboriginality originality classicality criticality cylindricality equivocality ethicality fantasticality farcicality illogicality impracticality inimicality musicality nonsensicality practicality pragmaticality reciprocality technicality theatricality logicality typicality unpracticality veridicality verticality animality whimsicality commonality conditionality constitutionality criminality directionality emotionality impersonality marginality multiple/split/ personality proportionality unconstitutionality municipality principality corporality immorality morality temporality unmorality hospitality inhospitality modality sodality locality vocality atonality polytonality tonality conjugality frugality plurality rurality duality individuality mutuality punctuality spirituality virtuality topicality tropicality amorality

(a mere) formality abnormality informality (mental) subnormality normality supernormality

Abnormality?

Seriously, there are good resources in existence for such things. Like a Thesaurus.

Here's a list from freethesaurus.net:

aberrance, aberrancy, abet, abnormality, abnormity, alienation, amorphism, anomalism, anomalousness, anomaly, bend, bias, brain damage, brainsickness, branching off, centrifugence, circuitousness, clouded mind, conceit, corner, crackpotism, crank, crankiness, crankism, craziness, crook, crosswiseness, crotchet, crotchetiness, curiosity, curve, daftness, decentralization, declination, defectiveness, deflection, deflexure, delusion, dementedness, dementia, departure, deployment, derangement, detour, deviance, deviancy, deviation, deviousness, diagonality, difference, differentness, digression, discursion, disorientation, distortion, distraction, divagation, divarication, divergence, divergency, diversion, division, dogleg, dottiness, double, drift, drifting, eccentricity, errancy, errantry, erraticism, erraticness, erroneousness, error, excursion, excursus, exorbitation, fallaciousness, fallacy, falseness, falsity, fanning, fanning out, fault, faultiness, flaw, flawedness, folie, foment, freakiness, freakishness, furor, hairpin, hamartia, heresy, heterodoxy, heteromorphism, idiocrasy, idiosyncrasy, illusion, indirection, indirectness, inferiority, insaneness, insanity, instigate, irrationality, irregularity, kink, loss of mind, loss of reason, lunacy, madness, maggot, mania, mannerism, mental deficiency, mental derangement, mental disease, mental disorder, mental disturbance, mental illness, mental instability, mental sickness, mind overthrown, mindsickness, misapplication, misconstruction, misdoing, misfeasance, misinterpretation, misjudgment, mistake, monstrosity, nonconformity, obliqueness, obliquity, oddity, oddness, peccancy, peculiarity, pererration, perversion, pixilation, possession, prodigy, provoke, psychopathy, queerness, quip, quirk, quirkiness, rabidness, raise, rambling, rarity, reasonlessness, self-contradiction, senselessness, separation, set, set on, shattered mind, sheer, shift, shifting, shifting course, shifting path, sick mind, sickness, sin, sinfulness, singularity, skew, skewness, slant, slip, splaying, spread, spreading, spreading out, squint, stir up, strangeness, straying, subnormality, superiority, sweep, swerve, swerving, swinging, tack, teratism, transverseness, trick, turn, turning, twist, unbalance, unbalanced mind, unconventionality, unnaturalism, unnaturalness, unorthodoxy, unsaneness, unsound mind, unsoundness, unsoundness of mind, untrueness, untruth, untruthfulness, vagary, variation, veer, wandering, warp, whim, whimsicality, whimsy, witlessness, wrong, wrongness, yaw, zigzag