From Frankish *werra (confusion, discord) — the same word became French 'guerre' and Spanish 'guerrilla.'
A state of armed conflict between different nations, states, or groups within a nation.
From Old North French 'werre' (war, conflict), from Frankish *werra (confusion, discord, strife), from Proto-Germanic *werzō (confusion, mixture), from PIE *wers- (to confuse, to mix up). The original meaning was 'confusion' or 'disorder' — war conceived as the breakdown of social order. The same root may have produced
'War' and 'guerrilla' are the same word at different stages. Frankish *werra became Old French 'werre' (→ English 'war') and Central French 'guerre' (→ Spanish 'guerra' → 'guerrilla,' literally 'little war'). The English and Spanish words for armed conflict are the same Germanic root that traveled through two different French dialects