idiot
dirtbrain
subnormal
stun
mentally challenged
halfwit
half-witted
dimwit
fool
stupidass
birdbrain
divvie
peon
half-brained
subintellectual
submoron
drool bucket
not the sharpest tool in the shed
not the sharpest tool in the box
simple
not the sharpest knife in the drawer
simpleton
unintelligence
cerebrally challenged
intellectually challenged
lackbrain
dumb genius
nonintellectual
subnormality
dipshidiot
subexpert
underbrained
stupid
unintelligent
retard
cretin
imbecile
unbright
moron
half-wit
changeling
fuckwad
nondescript
vacancy
simple-mindedly
muggle
dense
monkey
idiot savant
lackluster