The Collaborative International Dictionary of English v.0.48:

Compurgation \Com`pur*ga"tion\, n. [L. compurgatio, fr.
   compurgare to purify wholly; com- + purgare to make pure. See
   Purge, v. t.]
   1. (Law) The act or practice of justifying or confirming a
      man's veracity by the oath of others; -- called also
      wager of law. See Purgation; also Wager of law,
      under Wager.
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   2. Exculpation by testimony to one's veracity or innocence.
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            He was privileged from his childhood from suspicion
            of incontinency and needed no compurgation. --Bp.
                                                  Hacket.
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