" Military analysts use the term irregular warfare to describe conflicts that involve nonstate armed groups: combatants who don’t belong to the regular armed forces of nation-states. More broadly, the term irregular methods (sometimes asymmetric methods) describes techniques such as terrorism, guerrilla warfare, subversion, and cyberwarfare, which typically avoid direct confrontation with the military power of governments. "

― David Kilcullen , Out of the Mountains: The Coming Age of the Urban Guerrilla