(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
Bojidar	-	Bulgarian
Armide	-	Literature
Dominicus	do-MEE-nee-kus (Dutch)	Late Roman, Dutch
Jerome	[dʒə'rəum]
Imamu	-	Eastern African, Swahili
Carla	KAHR-lah (Spanish, German, Dutch), KAHR-lə (English)	Italian, Portuguese, Spanish, Catalan, English, German, Dutch