Swimming trunks are short garments a man swims in. A pair of swimming trunks.
Some pools abroad require them rather than shorts, which catches British visitors out. Swimming trunks are always plural, like trousers, and there is no singular.
1nounswimming trunksShort garments a man swims in.
“He had packed everything except swimming trunks.”
swimming trunks is clothing.
Practised in Clothes & Fashion