not know A from a windmill

not know A from a windmill

To be stupid. It references the vaguely similar shape of the letter A and a windmill. How do you manage to burn pasta? It's like you don't know A from a windmill.
See also: know, not, windmill
Farlex Dictionary of Idioms.
See also:
  • bonehead
  • not beat about the bush
  • bojangling
  • not beat around the bush
  • beat about the bush
  • beat around the bush
  • allude to
  • past
  • dipstick