campaign hat vs chapeau

campaign hat and chapeau both are nouns.

Word	Noun	Adjective	Verb	Adverb
campaign hat	Yes	No	No	No
chapeau	Yes	No	No	No

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

campaign hat: a broad-brimmed felt hat with a high crown; formerly worn by the United States Army and Marine personnel
chapeau: headdress that protects the head from bad weather; has shaped crown and usually a brim

Other hypernyms of campaign hat include hat, lid.

campaign hat (noun)	chapeau (noun)
a broad-brimmed felt hat with a high crown; formerly worn by the United States Army and Marine personnel	headdress that protects the head from bad weather; has shaped crown and usually a brim