Irregular military

thumb|In the 17th century, mercenaries were the backbone of European warfare, reaching their peak during the Thirty Years' War

group of people who undermine a larger group

any non-standard military organization

person who takes part in a resistance movement against an oppressive political or social establishment

individuals or groups that are wholly or partly independent of state governments and which threaten or use violence to achieve their goals

Belarusian combatant organisations opposed to Nazi Germany

resistance movement against the 2022 Russian invasion of Ukraine

Ruga-Ruga in German East Africa, 1914|thumb