gay woman vs gay

gay woman and gay both are nouns.

Word	Noun	Adjective	Verb	Adverb
gay woman	Yes	No	No	No
gay	Yes	Yes	No	No

As nouns, gay is a hypernym of gay woman; that is, gay is a word with a broader meaning than gay woman:

Other hypernyms of gay woman include homo, homophile, homosexual, adult female, woman.

gay woman (noun)	gay (noun)
a female homosexual	someone who is sexually attracted to persons of the same sex

gay woman (adjective)	gay (adjective)
	bright and pleasant; promoting a feeling of cheer
	brightly colored and showy
	homosexual or arousing homosexual desires
	given to social pleasures often including dissipation
	offering fun and gaiety
	full of or showing high-spirited merriment