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