The Collaborative International Dictionary of English v.0.48:

Abnegation \Ab`ne*ga"tion\, n. [L. abnegatio: cf. F.
   abn['e]gation.]
   a denial; a renunciation.
   [1913 Webster]

         With abnegation of God, of his honor, and of religion,
         they may retain the friendship of the court. --Knox.
   [1913 Webster]

WordNet (r) 3.0 (2006):

abnegation
    n 1: the denial and rejection of a doctrine or belief;
         "abnegation of the Holy Trinity"
    2: renunciation of your own interests in favor of the interests
       of others [syn: abnegation, self-abnegation, denial,
       self-denial, self-renunciation]

Moby Thesaurus II by Grady Ward, 1.0:

91 Moby Thesaurus words for "abnegation":
   abstinence, calm, calmness, conservatism, constraint, continence,
   contradiction, control, cool, declension, declination, declinature,
   declining, denial, deprivation, disagreement, disallowance,
   disclaimer, disclamation, disobedience, dispassion, dissent,
   evenness, forbearance, frugality, gentleness, golden mean,
   happy medium, holding back, impartiality, judiciousness,
   juste-milieu, lenity, meden agan, middle way, mildness,
   moderateness, moderation, moderationism, nay, naysaying, negation,
   negative, negative answer, negative attitude, negativeness,
   negativism, negativity, neutrality, nix, no, nonacceptance,
   noncompliance, nonconsent, nonobservance, nonviolence,
   nothing in excess, pacifism, prudence, recantation, refusal,
   rejection, renouncement, renunciation, repose, repudiation,
   restraint, retention, self-abnegation, self-control, self-denial,
   self-discipline, self-mastery, self-restraint, serenity, soberness,
   sobriety, sophrosyne, stability, steadiness, temperance,
   temperateness, thumbs-down, tranquillity, turndown,
   unexcessiveness, unextravagance, unextremeness, unwillingness,
   via media, withholding