airman vs adult male

airman and adult male both are nouns.

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

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

Other hypernyms of airman include aeronaut, aviator, flier, flyer, man.

airman (noun)	adult male (noun)
a male who operates an aircraft	an adult person who is male (as opposed to a woman)