A generic term for an individual with less-than-desirable qualities. Can also apply to an individual who has done something directly offensive to another. Usually employed when the name of the individual is not known, and it is typically used with disdain.
I can't believe that Joe Douchebag gave me a speeding ticket the other day. He was totally hating on me because of my out-of-state license plate!
What happened to your shirt?
Joe Douchebag spilled his beer on it after he ran into me near the bar. Asshole.