subexpert
outskilled
subintellectual
worse
underachiever
dense
inadequacy
slow on the uptake
skillessness
ham-fisted
subnormal
improficiency
unproficiency
dequalification
nonproficiency
inexpertness
fumbling
incompetent
bungling
clumsy
mentally challenged
ungenius
incompetence
light-witted
unsmart
obtuse
dim
dumb
slow
dull
underskilled
not the sharpest knife in the drawer
lackluster
indocible
not the sharpest tool in the shed
not the sharpest tool in the box
idiot
half-witted
submoron
stupid
amateurish
amateur
inexpert
unskilled
unadept
vacancy
feckless
normal for Norfolk
insufficiency
unworldly