Synonyms of costume in English:

costume


See definition of costume

noun

1‘there's a prize for the best costume’

SYNONYMS
outfit, ensemble, suit
dress, clothing, attire, garb, uniform, livery, array, regalia
clothes, garments, robes
informal get-up, gear, togs, garms, duds, glad rags
British informal clobber, kit, strip, rig-out
North American informal threads
formal apparel
literary raiment, habiliments
archaic vestments, vesture, habit

2‘if you'd like a dip, we can lend you a costume’

SYNONYMS
swimsuit, bathing suit, bathing costume, swimming costume, bikini
pair of swimming trunks, pair of trunks
informal cossie, swimming togs
Australian informal bathers, swimmers