geisha vs adult female

geisha and adult female both are nouns.

Word	Noun	Adjective	Verb	Adverb
geisha	Yes	No	No	No
adult female	Yes	No	No	No

As nouns, adult female is a hypernym of geisha; that is, adult female is a word with a broader meaning than geisha:

geisha: a Japanese woman trained to entertain men with conversation and singing and dancing
adult female: an adult female person (as opposed to a man)

Other hypernyms of geisha include Japanese, Nipponese, woman.

geisha (noun)	adult female (noun)
a Japanese woman trained to entertain men with conversation and singing and dancing	an adult female person (as opposed to a man)