shirtlifter vs adult male

shirtlifter and adult male both are nouns.

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

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

Other hypernyms of shirtlifter include gay, homo, homophile, homosexual, man.

shirtlifter (noun)	adult male (noun)
a homosexual man	an adult person who is male (as opposed to a woman)