widow woman vs woman

widow woman and woman both are nouns.

Word	Noun	Adjective	Verb	Adverb
widow woman	Yes	No	No	No
woman	Yes	No	No	No

As nouns, woman is a hypernym of widow woman; that is, woman is a word with a broader meaning than widow woman:

widow woman: a woman whose husband is dead especially one who has not remarried
woman: an adult female person (as opposed to a man)

Other hypernyms of widow woman include adult female.

widow woman (noun)	woman (noun)
a woman whose husband is dead especially one who has not remarried	women as a class
	an adult female person (as opposed to a man)
	a female person who plays a significant role (wife or mistress or girlfriend) in the life of a particular man