Peter Pan vs adult male

Peter Pan and adult male both are nouns.

Word	Noun	Adjective	Verb	Adverb
Peter Pan	Yes	No	No	No
adult male	Yes	No	No	No

As nouns, adult male is a hypernym of Peter Pan; that is, adult male is a word with a broader meaning than Peter Pan:

Peter Pan: a boyish or immature man; after the boy in Barrie's play who never grows up
adult male: an adult person who is male (as opposed to a woman)

Other hypernyms of Peter Pan include man.

Peter Pan (noun)	adult male (noun)
the main character in a play and novel by J. M. Barrie; a boy who won't grow up	an adult person who is male (as opposed to a woman)
a boyish or immature man; after the boy in Barrie's play who never grows up