The Collaborative International Dictionary of English v.0.48:
Schemer \Schem"er\, n. One who forms schemes; a projector; esp., a plotter; an intriguer. [1913 Webster] Schemers and confederates in guilt. --Paley. [1913 Webster]WordNet (r) 3.0 (2006):
schemer n 1: a planner who draws up a personal scheme of action [syn: schemer, plotter]