dim
nonintelligent
unintelligent
dull
nonsmart
unsmart
lackluster
unsmartness
stupidass
unbright
vacancy
unintellectual
gormless
unclever
underbrained
half-witted
ungroomed
unintelligence
stupid
short-witted
ungeeky
nonsavvy
not the sharpest tool in the box
halfwit
not the sharpest knife in the drawer
slow-witted
not the sharpest tool in the shed
intellectually challenged
cerebrally challenged
unintellectualized
mindless
light-witted
vacant
vacuous
doltish
unastute
cloistered
mentally challenged
ungenius
unskillful
simple-mindedly
sharp as a bowling ball
uninsightful
noninsightful
unknowledgeable
fool
unreasonably
uncleverness
subintellectual
nonintellectual