A villain with this flaw needs to be really powerful, or he will quickly become humorous. It can be taken by a "good guy", a paladin type of angelic self-confidence.
You are so sure of your abilities and superiority that you don't take your opponents seriously. You think of yourself as superior, not only in a physical sense, but also in a moral and ethical sense; you try to impress this fact upon others. In fact, opponents are childlike things that you wish to correct and put in their place, so that they will admit your superiority. You never consider an opponent to be a real danger or adjust your plans because of the opposition. You try hard not to kill those few who show some promise, you punish or teach them a lesson instead, so that they can learn the ultimate folly and despair of any path but yours.