ungenius
lackluster
uninventiveness
nongenius
unintelligence
lackbrain
cerebrally challenged
intellectually challenged
inexpertness
vacancy
nonvisionary
unvisionary
nonintelligent
unintelligent
nondiligence
dull
unskillfulness
nonproficiency
inexpertise
subexpert
improficiency
unproficiency
unskilfulness
inadequacy
skillessness
uncreativeness
unknowledgeable
untalented
underbrained
simplicity
dim
mentally challenged
unbright
unbrilliant
nontalent
unimaginativeness
outskilled
unskill
half-witted
lusterless
unartful
unworldly
inaptitude
gormless
unskillful
ham-fisted
blockish
underwitted
drool bucket
unsophisticated
inadept
talentlessness
ungifted
stun
divvie
monosynaptic
clumsy
incompetent
nontalented
halfwit
underproficient
fumbling
nonenmity
dense
stewpot
bungling
not the sharpest tool in the box
midget-minded
not the sharpest knife in the drawer
not the sharpest tool in the shed
underimagined
pinheaded
doltish
unscholarlike
insufficiency
stupid
dropkick
shtus
dyscompetence
untutoredness
uneducation
worse
brain damage
stockishness
numskullery
unastute
incapacity
unvalorous
dunderheadedness
thickheadedness
incogitancy
nonmastery
dunderheadism
light-witted