washman vs adult male

washman and adult male both are nouns.

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

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

Other hypernyms of washman include man, washer.

washman (noun)	adult male (noun)
a working woman who takes in washing	an adult person who is male (as opposed to a woman)