fanboy vs adult male

fanboy and adult male both are nouns.

Word	Noun	Adjective	Verb	Adverb
fanboy	Yes	No	No	No
adult male	Yes	No	No	No

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

fanboy: A male fan who is obsessive about a particular subject (especially, someone or something in popular entertainment media
adult male: an adult person who is male (as opposed to a woman)

Other hypernyms of fanboy include buff, devotee, fan, lover, man.

fanboy (noun)	adult male (noun)
A male fan who is obsessive about a particular subject (especially, someone or something in popular entertainment media	an adult person who is male (as opposed to a woman)