playing dumb

Verb

play dumb (third-person singular simple present plays dumb, present participle playing dumb, simple past and past participle played dumb)

1. (idiomatic, informal) To feign muteness.
   • I played dumb 'cause I knew if I talked at all, being simple and guileless, you all would twist me up and have the whole thing in a jiffy.1904, Rex Ellingwood Beach, “The Mule Driver and the Garrulous Mute”, in Pardners
2. (idiomatic, informal) To feign stupidity or ignorance of some knowledge, usually in order to avoid responsibility or gain some advantage.
   • Died. Virginia Hill, 49, redheaded, free-spending playmate of the underworld... who later acted out a cameo role before the late Senator Estes Kefauver's Senate crime committee, playing dumb about the business dealings of her many racketeer friends.1966 April 1, “Milestones”, in TIME, archived from the original on 12 May 2009

   Synonyms:

   play stupid