Men's Underwear

Terminology
There are several other terms for undergarments. Underclothes, underclothing and underwear are formal terms, while undergarments may be more casually called, in Australia, Reg Grundys (rhyming slang for undies) and Reginalds, and, in the United Kingdom, smalls (from the earlier smallclothes).
Women's undergarments collectively are called lingerie. They also are called intimate clothing and intimates.