early 15c., "vigor," from Middle French animosité (14c.) or directly from Latin animositatem (nominative animositas) "boldness, vehemence," from animosus "bold, spirited," from animus (see animus). Sense of "hostile feeling" is first recorded c. 1600, from a secondary sense in Latin (see animus).[animosity etymology, animosity origin, 英语词源]