dumber than a doornail

dumber than a doornail

Very stupid. You took apart the entire washing machine just to unblock the pump? I swear, sometimes you can be dumber than a doornail, Larry. I used to think that kid was dumber than a doornail, but he turned out to be a physicist.
See also: doornail, dumber
Farlex Dictionary of Idioms.
See also:
  • (as) dumb as a post
  • dumb as a post
  • (as) dumb as a fencepost
  • dumber
  • dumber than a bag of hammers
  • deader
  • deader than a doornail
  • swear down
  • swear
  • be (as) dead as a doornail