(as) dumb as a post

(as) dumb as a post

Very stupid or dumb. Are you dumb as a post? Why did you think you could fix the washing machine on your own?
See also: dumb, post

dumb as a post

AMERICAN, INFORMAL
If you describe someone as dumb as a post, you mean that they are very stupid. She's one of the most famous physicists in the country, and she's dumb as a post!
See also: dumb, post