(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
Nelu	-	Romanian
Bruce	[bru:s]
Oliver	AHL-ə-vər (English), AW-lee-ver (German), O-lee-ver (Finnish)	English, German, Swedish, Norwegian, Danish, Finnish, Estonian, Serbian, Croatian, Macedonian, Czech
Kiera	KEER-a, KEE-ar-a	Irish
Lugaid	-	Irish Mythology
Nero (2)	NE-ro	Italian