faked insanity

"Feigned madness" is a phrase used in popular culture to describe the assumption of a mental disorder for the purposes of evasion, deceit or the diversion of suspicion. In some cases, feigned madness may be a strategy — in the case of court jesters, an institutionalised one — by which a person acquires a privilege to violate taboos on speaking unpleasant, socially unacceptable, or dangerous truths.