From Longman Dictionary of Contemporary Englishbathing suitbathing suit /ˈbeɪðɪŋ suːt, -sjuːt $ -suːt/ noun [countable] old-fashioned 
DSSDCCa swimsuit
DSSDCCa swimsuitExamples from the Corpus
bathing suit• A more natural line evolved as bathing suit and fabric technology was improved to push, pull and lift invisibly.• She was looking very pretty in her bathing suit, her hair still damp from swimming.• His bathing suit was brief and white, the front of it enormous, set in wild bushes of escaping hair.• Babur puts on his new bathing suit and shows off. 