felt hat vs chapeau

felt hat and chapeau both are nouns.

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

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

felt hat: a hat made of felt with a creased crown
chapeau: headdress that protects the head from bad weather; has shaped crown and usually a brim

Other hypernyms of felt hat include hat, lid.

felt hat (noun)	chapeau (noun)
a hat made of felt with a creased crown	headdress that protects the head from bad weather; has shaped crown and usually a brim