The Collaborative International Dictionary of English v.0.48:

Enmity \En"mi*ty\, n.; pl. Enmities. [OE. enemyte, fr. enemy:
   cf. F. inimiti['e], OF. enemisti['e]. See Enemy, and cf.
   Amity.]
   1. The quality of being an enemy; hostile or unfriendly
      disposition.
      [1913 Webster]

            No ground of enmity between us known. --Milton.
      [1913 Webster]

   2. A state of opposition; hostility.
      [1913 Webster]

            The friendship of the world is enmity with God.
                                                  --James iv. 4.

   Syn: Rancor; hostility; hatred; aversion; antipathy;
        repugnance; animosity; ill will; malice; malevolence.
        See Animosity, Rancor.
        [1913 Webster]

WordNet (r) 3.0 (2006):

enmity
    n 1: a state of deep-seated ill-will [syn: hostility,
         enmity, antagonism]
    2: the feeling of a hostile person; "he could no longer contain
       his hostility" [syn: hostility, enmity, ill will]