1531, from M.Fr. hostilité "enmity," from L.L. hostilitatem (nom. hostilitas) "enmity," from L. hostilis, from hostis "enemy." Hostile (adj.) is 1487, from M.Fr. hostile "of or belonging to an enemy," from L. hostilis. As a noun meaning "enemy" it originally (1838) was used in ref. to N.Amer. Indians opposed to whites.
Main Entry: hos·til·i·ty Pronunciation: hä-'stil-&t-E Function: noun Inflected Form: plural-ties : conflict, opposition, or resistance in thought or principle —hos·tile/'häs-t&l, -"tIl/adjective