Synonyms and related words :
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