sunhat vs chapeau

sunhat and chapeau both are nouns.

Word	Noun	Adjective	Verb	Adverb
sunhat	Yes	No	No	No
chapeau	Yes	No	No	No

As nouns, chapeau is a hypernym of sunhat; that is, chapeau is a word with a broader meaning than sunhat:

sunhat: a hat with a broad brim that protects the face from direct exposure to the sun
chapeau: headdress that protects the head from bad weather; has shaped crown and usually a brim

Other hypernyms of sunhat include hat, lid.

sunhat (noun)	chapeau (noun)
a hat with a broad brim that protects the face from direct exposure to the sun	headdress that protects the head from bad weather; has shaped crown and usually a brim