dotard
subintellectual
doting
dimwit
doter
birdbrain
subnormal
Grandma Moses
nonintellectual
cheeser
lackbrain
how old are you
numskull
submoron
idiot
half-brained
stupidass
halfwit
boomer
imbecile
moron
half-wit
cretin
retard
nonsenior
old head on young shoulders
changeling
stun
fledgling
dirtbrain
naif
dodderer
technotard
oldling
superager
baby boy
fool
man child
senile
greenly
slow on the uptake
little
debutard
senior
incompetent
underbrained
lackluster
you can't put an old head on young shoulders
dotterel
elder
rube
acognitive
baby
nonexpert
stupid
idiot savant
gosling
yokel
unintelligent
bumpkin
quiz kid
hick
overintellectualized
hayseed
chawbacon
yahoo
not the sharpest tool in the shed
not the sharpest knife in the drawer
not the sharpest tool in the box
brainlet
dense
boy scout
tardlet
simpleton
simple
mentally deficient person
unintelligence
overintellectual
normal for Norfolk
monosynaptic
intellectually challenged
intelligent person
subexpert
mentally challenged
cerebrally challenged
cacophrenic
no spring chicken
buffty
unadept
cogent
age regressor
anti-intellectual
philistine
lowbrow
geezer
Peter Pan