straw hat vs hat

straw hat and hat both are nouns.

Word	Noun	Adjective	Verb	Adverb
straw hat	Yes	No	No	No
hat	Yes	No	Yes	No

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

straw hat: a stiff hat made of straw with a flat crown
hat: headdress that protects the head from bad weather; has shaped crown and usually a brim

Other hypernyms of straw hat include chapeau, lid.

straw hat (noun)	hat (noun)
a stiff hat made of straw with a flat crown	an informal term for a person's role
	headdress that protects the head from bad weather; has shaped crown and usually a brim

straw hat (verb)	hat (verb)
	put on or wear a hat
	furnish with a hat