The Collaborative International Dictionary of English v.0.48:

Contravene \Con`tra*vene"\, v. t. [imp. & p. p. Contravened;
   p. pr. & vb. n. Contravening.] [LL. contravenire; L. contra
   + venire to come: cf. F. contrevenir. See Come.]
   1. To meet in the way of opposition; to come into conflict
      with; to oppose; to contradict; to obstruct the operation
      of; to defeat.
      [1913 Webster]

            So plain a proposition . . . was not likely to be
            contravened.                          --Southey.
      [1913 Webster]

   2. To violate; to nullify; to be inconsistent with; as, to
      contravene a law.
      [1913 Webster]

            Laws that place the subjects in such a state
            contravene the first principles of the compact of
            authority.                            --Johnson.

   Syn: To contradict; set aside; nullify; defeat; cross;
        obstruct; baffle; thwart.
        [1913 Webster]

WordNet (r) 3.0 (2006):

contravene
    v 1: go against, as of rules and laws; "He ran afoul of the
         law"; "This behavior conflicts with our rules" [syn:
         conflict, run afoul, infringe, contravene]
    2: deny the truth of [syn: contradict, negate, contravene]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "contravene":
   abjure, breach, break, combat, contradict, cross, disaffirm,
   disclaim, disown, encroach, exclude, fight, gainsay, impugn,
   infract, infringe, intrude, negate, negative, offend, oppose,
   overstep, reject, repudiate, resist, spurn, transgress, traverse,
   trespass