Englishman vs adult male

Englishman and adult male both are nouns.

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

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

Other hypernyms of Englishman include English person, man.

Englishman (noun)	adult male (noun)
a man who is a native or inhabitant of England	an adult person who is male (as opposed to a woman)