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