guerrilla

Guerrilla refers to a form of irregular warfare in which small, mobile groups employ ambushes, raids, sabotage, and hit-and-run attacks against a larger, conventional army or occupying force. The term derives from the Spanish guerra (war) with the diminutive guera; it entered common use during the Peninsular War (1808–1814) to describe Spanish resistance fighters.

Guerrilla units are typically characterized by mobility, local support, and intimate knowledge of the terrain. They emphasize avoiding full-scale pitched battles and seek to degrade the enemy’s military effectiveness and political legitimacy through surprise and attrition. Tactics include ambushes on supply lines, raids on detachments or outposts, sabotage of infrastructure, intelligence gathering, and propaganda. Operationally, guerrilla forces often operate in small, autonomous cells or networks, enabling resilience and concealment and allowing rapid dispersal.

Historically, guerrilla warfare has been employed in many conflicts, including the Peninsular War, various Latin American wars of independence, World War II resistance movements, and the wars in Vietnam, Algeria, and Colombia. Notable modern examples include Viet Cong and North Vietnamese forces, Cuban and Colombian insurgencies, and other non-state armed groups that blend with civilian populations.

The effectiveness of guerrilla warfare depends on political context, foreign or internal support, and the ability to sustain civilian sympathy. Counterinsurgency campaigns typically combine military pressure with political concessions, development, and efforts to isolate guerrillas from local populations. The term can also refer to irregulars acting within broader insurgent campaigns, and it remains a generic descriptor for a spectrum of asymmetric fighting strategies.