geisha vs woman

geisha and woman both are nouns.

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

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

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

Other hypernyms of geisha include Japanese, Nipponese, adult female.

geisha (noun)	woman (noun)
a Japanese woman trained to entertain men with conversation and singing and dancing	women as a class
	an adult female person (as opposed to a man)
	a female person who plays a significant role (wife or mistress or girlfriend) in the life of a particular man