thick-witted

blockheaded brainless dazed deficient dense dim doltish dopey dull dumb dummy foolish futile gullible half-baked half-witted hebetudinous idiotic ill-advised imbecilic inane indiscreet insensate irrelevant laughable loser ludicrous meaningless mindless moronic naive nonsensical obtuse out to lunch pointless puerile rash senseless shortsighted simple simpleminded slow sluggish stolid stupefied thick thick-headed thickheaded trivial unintelligent unthinking witless