The Collaborative International Dictionary of English v.0.48:

Aver \A*ver"\ ([.a]*v[~e]r"), v. t. [imp. & p. p. Averred
   ([.a]*v[~e]rd"); p. pr. & vb. n. Averring.] [F. av['e]rer,
   LL. adverare, averare; L. ad + versus true. See Verity.]
   1. To assert, or prove, the truth of. [Obs.]
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   2. (Law) To avouch or verify; to offer to verify; to prove or
      justify. See Averment.
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   3. To affirm with confidence; to declare in a positive
      manner, as in confidence of asserting the truth.
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            It is sufficient that the very fact hath its
            foundation in truth, as I do seriously aver is the
            case.                                 --Fielding.
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            Then all averred I had killed the bird. --Coleridge.
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   Syn: To assert; affirm; asseverate. See Affirm.
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