agony aunt vs adult female

agony aunt and adult female both are nouns.

Word	Noun	Adjective	Verb	Adverb
agony aunt	Yes	No	No	No
adult female	Yes	No	No	No

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

agony aunt: a female newspaper columnist who answers questions and offers advice on personal problems to people who write in
adult female: an adult female person (as opposed to a man)

Other hypernyms of agony aunt include newspaper columnist, woman.

agony aunt (noun)	adult female (noun)
a female newspaper columnist who answers questions and offers advice on personal problems to people who write in	an adult female person (as opposed to a man)