waistcoat vs vest

waistcoat and vest both are nouns.

Word	Noun	Adjective	Verb	Adverb
waistcoat	Yes	No	No	No
vest	Yes	No	Yes	No

As nouns, waistcoat and vest are synonyms defined as:

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

waistcoat (verb)	vest (verb)
	clothe formally; especially in ecclesiastical robes
	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