Commando is an English language term meaning to go without underwear. It may refer to a man or a woman, and is often used in the phrase "going commando". However, it is particularly applied to females who do not wear panties and tights (N America, pantyhose) under a skirt or dress.
The term became popular after it was used in the TV series "Friends" in 1996.
In BDSM, it is often required by a Dominant as means of concentrating the submissive's or slave's mind on her condition. For instance, "I went commando for the weekend because Master required it". There are many opportunities for anxiety, for embarrassment, and for humiliation for the sub. Her body is instantly accessible at the lift of the skirt, or something may be revealed by accident during an upskirt glimpse, especially if the skirt is very short.
In the classic BDSM novel, Story of O, O is required to be without underwear and in a dress or skirt at all times. In the Gor novels by John Norman, this is referred to as the "no nether closure" principle of kajira attire (see Gor - Dictionary).