grass widower vs divorced man

grass widower and divorced man both are nouns.

Word	Noun	Adjective	Verb	Adverb
grass widower	Yes	No	No	No
divorced man	Yes	No	No	No

As nouns, grass widower and divorced man are synonyms defined as:

grass widower and divorced man: a man who is divorced from (or separated from) his wife

grass widower (noun)	divorced man (noun)
a man who is divorced from (or separated from) his wife	a man who is divorced from (or separated from) his wife