adj pertaining to, or engaged in, warfare carried on irregularly and by independent bands; as, a guerrilla party; guerrilla warfare.
2. guerrilla ·noun an irregular mode of carrying on war, by the constant attacks of independent bands, adopted in the north of spain during the peninsular war.
3. guerrilla ·noun one who carries on, or assists in carrying on, irregular warfare; especially, a member of an independent band engaged in predatory excursions in war time.