plain clothes vs vesture

plain clothes and vesture both are nouns.

Word	Noun	Adjective	Verb	Adverb
plain clothes	Yes	No	No	No
vesture	Yes	No	Yes	No

As nouns, vesture is a hypernym of plain clothes; that is, vesture is a word with a broader meaning than plain clothes:

plain clothes: ordinary clothing as distinguished from uniforms, work clothes, clerical garb, etc.
vesture: a covering designed to be worn on a person's body

Other hypernyms of plain clothes include article of clothing, clothing, habiliment, wear, wearable.

plain clothes (noun)	vesture (noun)
ordinary clothing as distinguished from uniforms, work clothes, clerical garb, etc.	a covering designed to be worn on a person's body
	something that covers or cloaks like a garment

plain clothes (verb)	vesture (verb)
	provide or cover with a cloak