What is a word for less intelligent?

brainless, deficient, dense, dumb, empty-headed, foolish, half-witted, idiotic, inane, meaningless, mindless, moronic, pointless, senseless, simple, simpleminded, slow, unthinking, witless, doltish.

How do you spell Unintelligently?

un·in·tel·li·gent

Having or displaying a lack or small amount of intelligence. un′in·tel′li·gence n.