means Open opposition, antagonism, or aggressive feeling directed toward someone or something perceived as an enemy or threat.

from From Latin 'hostilis,' meaning 'of an enemy,' built on 'hostis' — originally 'a stranger' before it hardened into 'enemy.' That same 'hostis' is a cousin of 'host' (in the welcoming sense) and 'guest,' all descended from a Proto-Indo-European root meaning 'stranger' or 'one with whom one has mutual obligations.' So the word carries a buried truth: the line between guest and enemy was always thin, depending on which way the stranger turned out to mean you.