Wreak vengeance on is an idiom meaning to take revenge or to exact retribution. It is usually used in a negative context, as it implies that someone has been wronged and is seeking justice. The term can be broken down into three parts: wreak, meaning to cause or inflict; vengeance, meaning retribution or revenge; and on, meaning directed at someone or something. Therefore, the phrase Wreak Vengeance On means to cause retribution or revenge against someone or something.