lazer-guided commentaries

Well at least it was fun. Oh, wait

I was sitting on the sofa chatting to Sally earlier this week, describing to her my heroic ride through the cold on the way back from Brighton. She wondered why I hadn't been wearing the windproof, waterproof one-piece suit I own. The one that, after a moment's thought, I realised I had been carrying with me. Both there and back. The one I'd completely forgotten about and that would have spared me a good three hours of arctic-level windchill.

What's the word for the opposite of "astute?" (thesaurus.reference.com suggests dense, dull, dumb, idiotic, imperceptive, naive, obtuse, retarded, slow, stupid, and unintelligent.)