Dark Jedi
A Jedi who has fallen to the Dark Side of the Force. Often used interchangably with the term Sith, although there is a distinction in method, training, and history between the Sith and the fallen members of the Jedi Order.
These Dark Jedi are Jedi who took an easy path in training and were not immediately discovered by their Masters, Force-sensitives with no training but natural talent who use it for personal gain or revenge. While dangerous, they are often as dangerous to themselves as to their victims, quickly degenerating under the Dark Side's toll.