adult female vs female person

adult female and female person both are nouns.

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

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

Other hypernyms of adult female include adult, grownup, female.

adult female (noun)	female person (noun)
an adult female person (as opposed to a man)	a person who belongs to the sex that can have babies