widow vs woman

widow and woman both are nouns.

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

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

Other hypernyms of widow include adult female.

widow (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

widow (verb)	woman (verb)
cause to be without a spouse