venom (n.)

mid-13c., venim, venym, "poison secreted by some animals and transferred by biting," from Anglo-French and Old French venim, venin "poison; malice," from Vulgar Latin *venimen (source also of Italian veleno, Spanish veneno), from Latin venenum "poison," earlier (pre-classical) "drug, medical potion," also "charm, seduction," probably originally "love potion," from PIE *wenes-no-, from root *wen- (1) "to desire, strive for." Variously deformed in post-Latin languages, apparently by dissimilation. Modern spelling in English from late 14c. The meaning "bitter, virulent feeling or language" is first recorded c. 1300.