A bathing suit is a piece of clothing which people wear when they go swimming. A swimming costume is a piece of clothing that is worn for swimming, especially by women and girls.

Is maillot de bain feminine?

maillot de bain {masculine}

What does Bain mean in English?

Bain, on the other hand, is a French word for bath. Here's an excerpt from The Word Detective: To say that something or someone is “the bane of my existence” means that the person or thing is a constant irritant or source of misery.