The Collaborative International Dictionary of English v.0.48:
Manipulator \Ma*nip"u*la`tor\, n. One who manipulates, sometimes in an underhanded or fraudulent manner; as, a stock market manipulator. [1913 Webster +PJC]WordNet (r) 3.0 (2006):
manipulator n 1: an agent that operates some apparatus or machine; "the operator of the switchboard" [syn: operator, manipulator] 2: a person who handles things manually