Here are some possible words:
damselfly
dancingly
dashingly
dastardly
debatably
decalcify
decidedly
decimally
declivity
defiantly
definably
deformity
democracy
dentistry
depravity
desirably
desultory
deviously
devotedly
dexterity
diathermy
dichotomy
dictatory
diffusely
digitally
dignitary
diplomacy
directory
direfully
discovery
disembody
disemploy
disparity
distantly
diurnally
diversely
diversify
diversity
dolefully
dollishly
doltishly
dormitory
dosimetry
doughtily
dragonfly
dromedary
drunkenly
dubiously
ductility
duplicity
duteously
dutifully
dysentery
dystrophy
Omega.
Arab
Antiestablishmentarianism
One word that fits your criteria is "distant." It starts with the letter 'd,' ends with 't,' and contains seven letters.
SUSSEX
shellfish
peninsula. phenomena.
Kangaroos
WHIRLPOOL
interview
Wonderful is a nine letter word. It begins with the letter w and ends with l.
Autonomic is a nine-letter word that indicates that you don't have to think about breathing.
cardboard
7 letter S words ending with M:serfdomsymptomsynonymsarcasmsanctumsunbeam
People who are elderly are said to be getting "on in years."
A seven letter word that starts with D and ends with T: decrypt
An eight letter word that starts with S and ends with T: satiristshortestsmallestsmarteststagnantstalwartstiffeststridentsubtract