disproof

from WordNet (r) 3.0 (2006)

disproof
    n 1: any evidence that helps to establish the falsity of
         something [syn: {disproof}, {falsification}, {refutation}]
    2: the act of determining that something is false [syn:
       {falsification}, {falsifying}, {disproof}, {refutation},
       {refutal}]

from The Collaborative International Dictionary of English v.0.48

Disproof \Dis*proof"\, n. [Pref. dis- + proof. Cf. {Disprove}.]
   A proving to be false or erroneous; confutation; refutation;
   as, to offer evidence in disproof of a statement.
   [1913 Webster]

         I need not offer anything farther in support of one, or
         in disproof of the other.                --Rogers.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

29 Moby Thesaurus words for "disproof":
      abjuration, abjurement, abrogation, absolute contradiction,
      annulment, contradiction, contrary assertion, contravention,
      controversion, countering, crossing, denial, disaffirmation,
      disallowance, disavowal, disclaimer, disclamation, disownment,
      forswearing, gainsaying, impugnment, nullification, recantation,
      refutation, renunciation, repudiation, retractation, retraction,
      revocation

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