fatheadedly
stockishly
pratty
stupidy
blockheadish
bodoh
thick as mince
simply
stupidass
bee-brained
opaque
numbskulled
simpleminded
dumbassed
one brick short of a full load
thick
retardical
numbnut
dumb as an ox
pillocky
dumbbutt
cockamamy
bull
stupidly
thick as pig shit
retarded
dumb as dirt
dumb as a stump
muddlebrained
shit-for-brains
dumber than a rock
thick as a whale omelette
dumb as a post
rock-dumb
dumb
goofball
dumb as a bag of hammers
sill
bubbleheaded
doltishly
dym
lamebrained
dopey
anserous
dumpily
goosish
twp
fool
baka
soft
sawney
lackwitted
dumb as nails
airheaded
sillily
insane
mad
fatuitous
dunderheaded
harebrained
boofheaded
dumbass
thickwitted
stupidicy
dumbfuckery
stupidish
foppery
rattlebrained
chuckleheaded
fuckwittedness
dumbish
boobery
retardation
sohai
overfoolish
asinine
anserine
inane
fatuous
hash
derpy
thick as two short planks
thick as a plank
tomfool
dumber than a box of rocks
stockishness
tomfoolish
ninnyish
dumb as a doorknob
doinky
stuuupid
brain damage
dunderheadism
dumbfounder
dunderheadedness
thickheadedness
numskullery
dumb as a box of rocks