The Collaborative International Dictionary of English v.0.48:

Barrator \Bar"ra*tor\, n. [OE. baratour, OF. barateor deceiver,
   fr. OF. barater, bareter, to deceive, cheat, barter. See
   Barter, v. i.]
   One guilty of barratry.
   [1913 Webster]

WordNet (r) 3.0 (2006):

barrator
    n 1: someone guilty of barratry [syn: barrator, barrater]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

BARRATOR, crimes. One who has been guilty of the offence of barratry.