Source : Webster's Revised Unabridged Dictionary (1913)

Rebutter \Re*but"ter\, n. (Law)
   The answer of a defendant in matter of fact to a plaintiff's
   surrejoinder.

Source : WordNet®

rebutter
     n 1: a debater who refutes or disproves by offering contrary
          evidence or argument [syn: {disprover}, {refuter}, {confuter}]
     2: (law) a pleading by the defendant in reply to a plaintiff's
        surrejoinder [syn: {rebuttal}]