thick as two short planks
conehead
dumb as a doorknob
dumb as a box of rocks
dumber than a box of rocks
thick as mince
puzzlewit
boofheaded
dumbnut
stupidass
stupidish
glype
stupidly
hammerhead
plank
dumb as dirt
thick as a whale omelette
thickwitted
shit-for-brains
booger brain
fuckwit
dumb as a post
shitwit
chuckleheaded
dumber than a rock
retarded
thick as pig shit
dumb as a stump
dumb
rock-dumb
haramzada
momo
thick
mo
cheesehead
numbnut
beetlehead
bull
retardical
dumb as an ox
moke
dunderheaded
jamoke
one brick short of a full load
clod
log
dumbbutt
dumbass
mislest
jinnet