noun
(1) A shrewd or unscrupulous person who knows how to circumvent difficulties
(2) An agent that operates some apparatus or machine
"The operator of the switchboard"
(3) Someone who owns or operates a business
"Who is the operator of this franchise?"
(4) A speculator who trades aggressively on stock or commodity markets
(5) (mathematics) a symbol that represents a function from functions to functions
"The integral operator"