nightwear vs wear

nightwear and wear both are nouns.

Word	Noun	Adjective	Verb	Adverb
nightwear	Yes	No	No	No
wear	Yes	No	Yes	No

As nouns, wear is a hypernym of nightwear; that is, wear is a word with a broader meaning than nightwear:

Other hypernyms of nightwear include article of clothing, clothing, habiliment, vesture, wearable.

nightwear (noun)	wear (noun)
garments designed to be worn in bed	the act of having on your person as a covering or adornment
	a covering designed to be worn on a person's body
	impairment resulting from long use

nightwear (verb)	wear (verb)
	be dressed in
	put clothing on one's body
	have or show an appearance of
	exhaust or get tired through overuse or great strain or stress
	have on one's person
	deteriorate through use or stress
	go to pieces
	last and be usable
	have in one's aspect; wear an expression of one's attitude or personality