Source : Webster's Revised Unabridged Dictionary (1913)

Improbation \Im`pro*ba"tion\, n. [L. improbatio.]
   1. The act of disapproving; disapprobation.

   2. (Scots Law) The act by which falsehood and forgery are
      proved; an action brought for the purpose of having some
      instrument declared false or forged. --Bell.