give your head a shake

(redirected from give one's head a shake)

give your head a shake

An imperative to reevaluate one's ideas, behavior, actions, etc., or to begin acting or thinking sensibly. Primarily heard in Canada. You need to give your head a shake if you really think ghosts exist. Give your head a shake, John—no one is going to pay for a service they already get for free.
See also: give, head, shake