widower vs adult male

widower and adult male both are nouns.

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

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

Other hypernyms of widower include man.

widower (noun)	adult male (noun)
a man whose wife is dead especially one who has not remarried	an adult person who is male (as opposed to a woman)