dumben
dumb
dumbfounder
dumbify
dumb like a fox
stare like a stuck pig
duncify
dunderheaded
dumbass
stupidish
dumb as nails
stuuupid
beclown
blockhead
muddlebrained
lamebrained
simpleminded
stupidly
dumbassed
thickhead
dumb as a rock
numbskulled
numbnut
retardical
dumb as an ox
thick
bull
dumbbutt
stonker
one brick short of a full load
dumb as a box of rocks
dumbish
thick as a plank
thick as two short planks
dumb as a doorknob
dumber than a box of rocks
tomfool
dumbshit
dumb bunny
twonk
ass
dumbo
booby
boaby
dullwit
fridge magnet
dummy
dym
smooth brain
stupidity