jackassinine
adj. Without common sense or the slightest trace of intelligence. Two steps beyond asinine. Often used in the context of road rage, as the multisyllabic nature demands more energy to say, thus releasing additional stress in its expression.
I can't believe that idiot just pulled right out in front of me like he was in a huge hurry, and is now going 15 miles below the speed limit! What a jackassinine thing to do!