aviatrix vs adult female

aviatrix and adult female both are nouns.

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

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

Other hypernyms of aviatrix include aeronaut, aviator, flier, flyer, woman.

aviatrix (noun)	adult female (noun)
a woman aviator	an adult female person (as opposed to a man)