Hell, I can do better on my own with this...

Chuckle-headed, moronic, dimwitted, obtuse, dense, dull, half-witted, witless, idiotic, feckless, slow, lacking intelligence, inept, foolish, lacking judgement, less than shrewd, vapid, vacuous, empty-headed, know-nothing, brainless, incompetent, unthinking, thoughtless, thick-headed, mentally challenged, dull, dunderheaded, neanderthal, apish, oxlike, dumb (as in "dumbass"), doltish, cretinous...

Well, that's a start anyway...I know I've missed some of the archaic ones.

- LH