drop off vs wharf

drop off is not a noun while wharf is a noun.

Word	Noun	Adjective	Verb	Adverb
drop off	No	No	Yes	No
wharf	Yes	No	Yes	No

As verbs, wharf is a hyponym of drop off; that is, wharf is a word with a more specific, narrower meaning than drop off:

Other hyponyms of drop off include air-drop.

drop off (noun)	wharf (noun)
	a platform built out from the shore into the water and supported by piles; provides access to ships and boats

drop off (verb)	wharf (verb)
change from a waking to a sleeping state	moor at a wharf
fall to a lower standard	discharge at a wharf
fall or diminish	come into or dock at a wharf
retreat	store on a wharf
remove (cargo, people, etc.) from and leave	provide with a wharf