An acronym pronounced like "honk." It refers to a "Dick," "Dumb-ass," "Douche," (or other "D" word) ON a Cell-phone. Most often applied to a person who is so busy talking on the cell phone that they drive like an idiot, eg: drive ten miles under the speed limit, don't use their mirrors, don't signal, etc. It can also be applied to a cell user in other circumstances like a movie theater, elevator, or other inappropriate/annoying places.
"Man, that donc just cut me off!"
"I wish that donc would hang up and drive!"
"If that donc doesn't hang up when the movie starts, I'm going to throw my show at him!"