drop off vs fall asleep

drop off and fall asleep both are verbs.

Word	Noun	Adjective	Verb	Adverb
drop off	No	No	Yes	No
fall asleep	No	No	Yes	No

As verbs, drop off and fall asleep are synonyms defined as:

Other synonyms of drop off include dope off, doze off, drift off, drowse off, flake out, nod off.

drop off (verb)	fall asleep (verb)
change from a waking to a sleeping state	change from a waking to a sleeping state
fall to a lower standard
fall or diminish
retreat
remove (cargo, people, etc.) from and leave