The Collaborative International Dictionary of English v.0.48:

Disprove \Dis*prove"\, v. t. [imp. & p. p. Disproved; p. pr. &
   vb. n. Disproving.] [Pref. dis- + prove: cf. OF.
   desprover.]
   1. To prove to be false or erroneous; to confute; to refute.
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            That false supposition I advanced in order to
            disprove it.                          --Atterbury.
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   2. To disallow; to disapprove of. [Obs.] --Stirling.
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