be as thick as two short planks

(British informal) also be as thick as shit (British taboo!)

to be very stupid He might be good-looking but he's as thick as two short planks. Most of the people who read these papers are as thick as shit anyway.

Common Names:

Name	Pronounced	Usage
Sacheverell	sə-SHEV-ər-əl	English (Rare)
Myrrine	-	Ancient Greek
RosÁRio	roo-ZA-ryoo	Portuguese
Leonard	LEN-ərd (English), LAY-o-nahrt (Dutch)	English, Dutch, German, Ancient Germanic
Yvonne	[i'vɔn]
Jessie (2)	JES-ee	English