Any person unfortunately possessing characteristics of both a complete idiot and an asshole. They typically have no brain and or common sense and tend to get on people's bad sides with their impeccable stupidity.
"Last night at the bar Kevin was being SUCH a douche-tard"
Any individual that makes a statement that is so obnoxious that you can't decide between calling them a douche bag or a retard, so you call them a douche tard.