(as) thick as two short planks

Remarkably stupid, dimwitted, or obtuse. I smoked a lot of marijuana when I was in high school, so I turned out thick as two short planks by the time I finally graduated. Jen's new girlfriend is very nice, but she's as thick as two short planks.

Common Names:

Name	Pronounced	Usage
CÂNdida	-	Portuguese
Caspian	KAS-pee-ən (English)	Literature
Cassander	-	Ancient Greek (Latinized)
MÌCheal	-	Scottish
Marcela	mahr-THE-lah (Spanish), mahr-SE-lah (Latin American Spanish), mahr-TSE-lah (Polish), mahr-CHE-lah (Romanian), MAHR-tse-lah (Czech)	Spanish, Polish, Romanian, Czech
Ivey	['aivi]