washerman vs adult male

washerman and adult male both are nouns.

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

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

Other hypernyms of washerman include man, washer.

washerman (noun)	adult male (noun)
a man who operates an industrial washing machine	an adult person who is male (as opposed to a woman)