sou'wester vs chapeau

sou'wester and chapeau both are nouns.

Word	Noun	Adjective	Verb	Adverb
sou'wester	Yes	No	No	No
chapeau	Yes	No	No	No

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

sou'wester: waterproof hat with wide slanting brim longer in back than in front
chapeau: headdress that protects the head from bad weather; has shaped crown and usually a brim

Other hypernyms of sou'wester include hat, lid.

sou'wester (noun)	chapeau (noun)
waterproof hat with wide slanting brim longer in back than in front	headdress that protects the head from bad weather; has shaped crown and usually a brim
a strong wind from the southwest