be (as) thick as a short plank

be (as) thick as a short plank

To be remarkably stupid, dimwitted, or obtuse. I smoked a lot of marijuana when I was in high school, so I was as thick as a short plank by the time I finally graduated. Jen's new girlfriend is very nice, but she's thick as a short plank.
See also: plank, short, thick
Farlex Dictionary of Idioms.
See also:
  • (as) thick as two short planks
  • thick as two short planks
  • be (as) thick as a brick
  • (as) thick as a brick
  • thick as two planks
  • (as) thick as two planks