chapeau vs headdress

chapeau and headdress both are nouns.

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

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

chapeau: headdress that protects the head from bad weather; has shaped crown and usually a brim
headdress: clothing for the head

Other hypernyms of chapeau include headgear.

chapeau (noun)	headdress (noun)
headdress that protects the head from bad weather; has shaped crown and usually a brim	clothing for the head