authoress vs adult female

authoress and adult female both are nouns.

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

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

Other hypernyms of authoress include woman, author, writer.

authoress (noun)	adult female (noun)
a woman author	an adult female person (as opposed to a man)