Violence is an expression of physical force against yourself or against any other person deliberately or as result of getting hurt by any mean.
The violence has many different faces, the physical violence face is more common but there are the political violence, the social violence, the economical violence and using people. Also, there is another face called the symbolic violence that appears on daily communication as reflection of the traditions and the social norms.
The violence has no legitimacy, even if it serves a good case or to beat the violence itself, because the only thing comes out of violence is violence, and the only way left to beat the violence is PEACE.