(as) dumb as a box of rocks

(as) dumb as a box of rocks

Very stupid. Are you dumb as a box of rocks? Why did you think you could fix the washing machine on your own? I used to think that kid was a as dumb as a box of rocks, but he turned out to be a physicist.
See also: box, dumb, of, rock
Farlex Dictionary of Idioms.
See also:
  • hit the big one
  • (as) dumb as a post
  • dumb as a post
  • go against the flow
  • bonehead
  • dread
  • dumb
  • (someone) thinks (they) are so smart
  • blue on blue
  • capable of doing