kinsman vs adult male

kinsman and adult male both are nouns.

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

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

Other hypernyms of kinsman include relation, relative, man.

kinsman (noun)	adult male (noun)
a male relative	an adult person who is male (as opposed to a woman)