The Collaborative International Dictionary of English v.0.48:

Repudiate \Re*pu"di*ate\ (r[-e]*p[=u]"d[i^]*[=a]t), v. t. [imp.
   & p. p. Repudiated (-?`t?d); p. pr. & vb. n.
   Repudiating.] [L. repudiatus, p. p. of repudiare to
   repudiate, reject, fr. repudium separation, divorce; pref.
   re- re- + pudere to be ashamed.]
   [1913 Webster]
   1. To cast off; to disavow; to have nothing to do with; to
      renounce; to reject.
      [1913 Webster]

            Servitude is to be repudiated with greater care.
                                                  --Prynne.
      [1913 Webster]

   2. To divorce, put away, or discard, as a wife, or a woman
      one has promised to marry.
      [1913 Webster]

            His separation from Terentis, whom he repudiated not
            long afterward.                       --Bolingbroke.
      [1913 Webster]

   3. To refuse to acknowledge or to pay; to disclaim; as, the
      State has repudiated its debts.
      [1913 Webster]

WordNet (r) 3.0 (2006):

repudiate
    v 1: cast off; "She renounced her husband"; "The parents
         repudiated their son" [syn: disown, renounce,
         repudiate]
    2: refuse to acknowledge, ratify, or recognize as valid; "The
       woman repudiated the divorce settlement"
    3: refuse to recognize or pay; "repudiate a debt"
    4: reject as untrue, unfounded, or unjust; "She repudiated the
       accusations"

Moby Thesaurus II by Grady Ward, 1.0:

141 Moby Thesaurus words for "repudiate":
   abandon, abjure, abrogate, apostatize, assert the contrary,
   back down, back out, backwater, ban, bar, bar out, be unmoved,
   be unwilling, beg off, belie, blockade, brush aside, cast, chuck,
   chuck out, climb down, contemn, contest, contradict, contravene,
   controvert, count out, counter, crawfish out, cross, cut off,
   debar, decline, decline to accept, default, deny, desert, despise,
   disaffirm, disagree, disallow, disapprove, disavow, discard,
   disclaim, discount, disdain, dishonor, dismiss, disown, disprove,
   dispute, disregard, dissent, eat crow, eat humble pie, embargo,
   except, exclude, forgo, forsake, forswear, freeze out, gainsay,
   hold out against, ignore, impugn, join issue upon, keep out,
   leave out, levant, lock out, negate, negative, not accept,
   not admit, not buy, not consent, not hear of, not pay,
   not think of, nullify, omit, oppose, ostracize, pass by, pass over,
   pass up, preclude, prohibit, protest, push aside, rat, rebuff,
   recant, refuse, refuse consent, refuse to admit,
   refuse to consider, refuse to pay, refute, reject, relegate,
   renege, renounce, repel, reprobate, repulse, rescind,
   resist entreaty, resist persuasion, retract, reverse, revoke,
   say nay, say no, scorn, scout, send to Coventry, shove away,
   shut out, spurn, stand aloof, stop payment, swallow, taboo,
   take back, take issue with, tergiversate, throw away, throw out,
   turn, turn away, turn down, turn out, unsay, vote nay,
   vote negatively, waive, welsh, withdraw