non-violent adj.

a prefix used freely in English and meaning "not, lack of," or "sham," giving a negative sense to any word, 14c., from Anglo-French noun-, from Old French non-, from Latin non "not, by no means, not at all, not a," from Old Latin noenum "not one" (*ne oinom, from PIE root *ne- "not" + PIE root *oi-no- "one, unique"). In some cases perhaps from Middle English non "not" (adj.), from Old English nan (see not). "It differs from un- in that it denotes mere negation or absence of the thing or quality, while un- often denotes the opposite of the thing or quality" [Century Dictionary].

mid-14c., from Old French violent or directly from Latin violentus, related to violare (see violation). In Middle English the word also was applied in reference to heat, sunlight, smoke, etc., with the sense "having some quality so strongly as to produce a powerful effect." Related: Violently.