A pompous and inconsiderate person suffering from illusions of importance and grandeur. This person may also exhibit general hostility toward others and display an air of genuine douche baggery if confronted. Such person may make reference to him/herself by using the third person.
Ex: The dude who drives the blindingly yellow Porsche convertible that double-parks each day in the filled to capacity parking garage is a real Ass Clown!
Ex: The dude who just spilled beer on a group of old ladies while plowing through three kids to catch that foul ball at the Royals v. Blue Jays spring training game is a real Ass Clown!