unintelligent (adj.)
- artless
- awkward
- brainless
- callow
- dumb
- empty
- empty-headed
- fatuous
- foolish
- gauche
- green
- groping
- headless
- ignorant
- inane
- inapt
- inattentive
- inefficient
- inept
- inexperienced
- inexpert
- innocent
- insensate
- irrational
- mediocre
- mindless
- naive
- nescient
- pedestrian
- poor
- raw
- reasonless
- senseless
- simple
- tentative
- thoughtless
- unacquainted
- uncomprehending
- unenlightened
- unfamiliar
- unilluminated
- uninformed
- uninitiated
- unknowing
- unreasoning
- unripe
- unskillful
- unsure
- untalented
- unthinking
- unversed
- unwise
- vacuous
- weak
- witless
