go commando
To not wear underwear (chiefly underpants) under one's outer clothing
Ross: … why do you have to wear underwear tonight? Joey: It's a rented tux, 'kay? I'm not gonna go commando in another man's fatigues.
noun
A small fighting force specially trained for making quick destructive raids against enemy-held areas.
The most important objective was at Batna itself, where a group of three commandos each comprising ten men was to attack Deleplanque's sub-prefecture […].
A commando trooper.
Ben Grant, 30, who spent more than five years as a commando in the Royal Marines, is part of group of seven ex-servicemen who arrived in Ukraine over the weekend to fight invading Russian forces.
An organized force of Boer troops in South Africa; a raid by such troops.