bandeau vs brassiere

bandeau and brassiere both are nouns.

Word	Noun	Adjective	Verb	Adverb
bandeau	Yes	No	No	No
brassiere	Yes	No	No	No

As nouns, bandeau and brassiere are synonyms defined as:

bandeau and brassiere: an undergarment worn by women to support their breasts

Other synonyms of bandeau include bra.

bandeau (noun)	brassiere (noun)
an undergarment worn by women to support their breasts	an undergarment worn by women to support their breasts