tie up vs wharf

tie up is not a noun while wharf is a noun.

Word	Noun	Adjective	Verb	Adverb
tie up	No	No	Yes	No
wharf	Yes	No	Yes	No

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

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

tie up (verb)	wharf (verb)
secure with or as if with ropes	moor at a wharf
finish the last row	discharge at a wharf
restrain from moving or operating normally	come into or dock at a wharf
secure in or as if in a berth or dock	store on a wharf
invest so as to make unavailable for other purposes	provide with a wharf