The Collaborative International Dictionary of English v.0.48:

ambivalence \ambivalence\, ambivalency \ambivalency\n.
   1. mixed feelings or emotions; uncertainty or vacillation in
      making a choice.
      [WordNet 1.5 +PJC]

   2. (Psychol.) the simultaneous existence within a person of
      both positive and negative feelings toward another person
      or action, or toward an object (as of attraction and
      revulsion), resulting in internal conflict.
      [PJC]

WordNet (r) 3.0 (2006):

ambivalence
    n 1: mixed feelings or emotions [syn: ambivalence,
         ambivalency]

Moby Thesaurus II by Grady Ward, 1.0:

82 Moby Thesaurus words for "ambivalence":
   Janus, ambiguity, ambitendency, ambivalence of impulse, antinomy,
   asymmetry, biformity, bifurcation, capriciousness, change of mind,
   changeableness, conflict, conjugation, decompensation, dichotomy,
   disproportion, disproportionateness, double-mindedness, doubleness,
   doublethink, doubling, dualism, duality, dubiety, dubiousness,
   duplexity, duplication, duplicity, emotional shock, equivocality,
   equivocation, external frustration, fence-sitting,
   fence-straddling, fickleness, frustration, halving, heresy,
   heterodoxy, heterogeneity, incoherence, incommensurability,
   incompatibility, incongruity, inconsistency, inconsonance,
   inconstancy, indecision, indecisiveness, infirmity of purpose,
   instability, irony, irreconcilability, irresolution, mental shock,
   mercuriality, mugwumpery, mugwumpism, nonconformability,
   nonconformity, oxymoron, pairing, paradox, polarity,
   psychological stress, second thoughts, self-contradiction, stress,
   tergiversation, trauma, traumatism, twinning, two-facedness,
   twoness, uncertainty, unconformability, unconformity,
   undecidedness, undeterminedness, unorthodoxy, unsettledness,
   unsettlement