Not wearing underpants under outer clothing is known in American slang as freeballing for men and as going commando Women's brassieres provide support for the breasts, and men's briefs serve the same function for the male genitalia.
A corset may be worn as a foundation garment to alter a woman's body shape.
Some items of clothing are designed exclusively as underwear, while others such as T-shirts and certain types of shorts are suitable both as underwear and as outer clothing.
In the Middle Ages, western men's underwear became looser fitting.
The loincloth was replaced by loose, trouser-like clothing called braies, which the wearer stepped into and then laced or tied around the waist and legs at about mid-calf.
The suitability of underwear as outer clothing is, apart from the indoor or outdoor climate, largely dependent on societal norms, fashion, and the requirements of the law.
If made of suitable material, some underwear can serve as nightwear or swimsuits.