widower vs widowman

widower and widowman both are nouns.

Word	Noun	Adjective	Verb	Adverb
widower	Yes	No	No	No
widowman	Yes	No	No	No

As nouns, widower and widowman are synonyms defined as:

widower and widowman: a man whose wife is dead especially one who has not remarried

widower (noun)	widowman (noun)
a man whose wife is dead especially one who has not remarried	a man whose wife is dead especially one who has not remarried