artless awkward blankminded brainless callow dumb empty empty-headed fatuous foolish gauche green groping half-assed headless ignorant inadept inane inapt inattentive inefficient inept inexperienced inexpert innocent insensate irrational know-nothing lackbrained lean-minded lean-witted mediocre mindless naive nescient not bright of little brain pea-brained pedestrian pin-brained poor raw reasonless senseless simple skill-less slackminded slackwitted strange to tentative thoughtless unacquainted unapprized unapt uncomprehending unconversant undeft undexterous undextrous unenlightened unfacile unfamiliar ungifted unilluminated uninformed uninitiated unintellectual unknowing unposted unproficient unreasoning unripe unskillful unsure untalented unthinking unversed unwise vacuous weak witless