Someone that is up to douche baggery. One who asks you a question, and then disagrees with the answer you give them. Mark St. D. does this frequently.
Mark: How does a ___(insert random car part) work?
you: _____(insert explanation of said part)
Mark: NO its does'nt thats wrong and you are a moron.
you: ok D. bag (other acceptable write offs are, ok drift king and ok D. king)