Source : Webster's Revised Unabridged Dictionary (1913)

Machinator \Mach"i*na`tor\, n. [L.]
   One who machinates, or forms a scheme with evil designs; a
   plotter or artful schemer. --Glanvill. Sir W. Scott.

Source : WordNet®

machinator
     n : a member of a conspiracy [syn: {conspirator}, {coconspirator},
          {plotter}]