fit out vs vest

fit out is not a noun while vest is a noun.

Word	Noun	Adjective	Verb	Adverb
fit out	No	No	Yes	No
vest	Yes	No	Yes	No

As verbs, vest is a hyponym of fit out; that is, vest is a word with a more specific, narrower meaning than fit out:

fit out (noun)	vest (noun)
	a collarless men's undergarment for the upper part of the body
	a man's sleeveless garment worn underneath a coat

fit out (verb)	vest (verb)
provide with clothes or put clothes on	clothe formally; especially in ecclesiastical robes
provide with (something) usually for a specific purpose	clothe oneself in ecclesiastical garments
	place (authority, property, or rights) in the control of a person or group of persons
	become legally vested
	provide with power and authority