Briefs are a type of short, form-fitting underwear and swimwear, as opposed to styles where material extends down the thighs. Briefs have various different styles, usually with a waistband attached to fabric that runs along the pelvis to the crotch and buttocks, and are worn by both men and women. Swim briefs are a variation used as swimwear.

Underwear, underclothing, or undergarments are items of clothing worn beneath outer clothes, usually in direct contact with the skin, although they may comprise more than a single layer. They serve to keep outer clothing from being soiled or damaged by bodily excretions, to lessen the friction of outerwear against the skin, to shape the body, and to provide concealment or support for parts of it. In cold weather, long underwear is sometimes worn to provide additional warmth. Special types of undergarments have religious significance. Some items of clothing are designed as undergarments, while others, such as T-shirts and certain types of shorts, are appropriate both as underwear and outerwear. If made of suitable material or textile, some underwear can serve as nightwear or swimwear, and some undergarments are intended for sexual attraction or visual appeal.