a member of a band of irregular soldiers that uses guerrilla warfare, harassing the enemy by surprise raids, sabotaging communication and supply lines, etc.
adjective
pertaining to such fighters or their technique of warfare: guerrilla strongholds;guerrilla tactics.
of or relating to an unauthorized, edgy, or disruptive version of an activity: guerrilla filmmaking on a busy sidewalk;guerilla gardening to beautify an abandoned lot.
Origin of guerrilla
First recorded in 1800–10; from Spanish, diminutive of guerra “war” (of Germanic origin) + -illa diminutive suffix; originally in reference to the Spanish resistance against Napoleon; the name for the struggle erroneously taken as a personal noun; cf. war1, -elle
a member of an irregular usually politically motivated armed force that combats stronger regular forces, such as the army or police
(as modifier)guerrilla warfare
a form of vegetative spread in which the advance is from several individual rhizomes or stolons growing rapidly away from the centre, as in some cloversCompare phalanx