woman's hat vs hat

woman's hat and hat both are nouns.

Word	Noun	Adjective	Verb	Adverb
woman's hat	Yes	No	No	No
hat	Yes	No	Yes	No

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

woman's hat: hats for women; the wares sold by a milliner
hat: headdress that protects the head from bad weather; has shaped crown and usually a brim

Other hypernyms of woman's hat include chapeau, lid.

woman's hat (noun)	hat (noun)
hats for women; the wares sold by a milliner	an informal term for a person's role
	headdress that protects the head from bad weather; has shaped crown and usually a brim

woman's hat (verb)	hat (verb)
	put on or wear a hat
	furnish with a hat