Disbarment is a form of discipline of a lawyer resulting in the loss (often permanently) of that lawyer's right to practice law. It is contrasted with censure or suspension.
For example, Mike Nifong was disbarred for his prosecution of the innocent Duke lacrosse players in 2006. Fred Phelps, better known as the former pastor of the Westboro Baptist Church, was also a lawyer who was disbarred (by agreement) after filing numerous frivolous lawsuits against persons attempting to sue him.