opaque
one brick short of a full load
retardical
numbnut
dumb as an ox
dumbbutt
thick
bull
simpleminded
numbskulled
dumbassed
dunderheaded
dumbass
dopey
bubbleheaded
muddlebrained
dumb as a bag of hammers
pratty
bodoh
blockheadish
thick as mince
stupidy
lamebrained
dumb as nails
stupidass
stupidish
goofball
sill
boofheaded
dumber than a rock
thick as pig shit
baka
shit-for-brains
dumb as a stump
retarded
dumb as dirt
dumb
rock-dumb
thick as a whale omelette
dumb as a post
dumbish
soft
goosish
twp
fool
dumb as a doorknob
dumb as a box of rocks
derpy
dumber than a box of rocks
crackbrained
thick as two short planks
thick as a plank
thickwitted
dym