Guer-rī'lā1, n.
(gər-rīl'la), n. [Sp., literally little war, skirmish, diminutive of guerra, war; Pr., It., & Pg. also guerra, Fr. guerre, from O. H. Ger. werra, scandal, A-S. wār, O. Eng. werre, Eng. war, from O. H. Ger. & O. Sax. werran, N. H. Ger. wirren, to confound, overturn.]
Sense 1. An irregular mode of carrying on war, by the constant attacks of independent bands, adopted in the north of Spain during the Peninsular war.
Sense 2. One who carries on, or assists in carrying on, irregular warfare; especially a member of an independent band engaged in predatory excursions against an enemy. [Written also guerrilla.]
☞ The term guerrilla is the diminutive of the Spanish word guerra, war, and means petty war, that is, war carried on by detached parties; generally in the mountains. . . . A guerrilla party means an irregular band of armed men, carrying on an irregular war, not being able, according to their character as a guerrilla party, to carry on what the law terms a regular war. The irregularity of the guerrilla party consists in its origin, for it is either self-constituted or constituted by the call of a single individual, not according to the general law of levy, conscription, or volunteering; it consists in its disconnection with the army, as to its pay, provision, and movements, and it is irregular as to the permanency of the band, which may be dismissed and called again together at any time. F. Lieber.