A person who opposes the use of war or violence to settle a dispute is called a pacifist. If you are a pacifist, you talk through your differences with others instead of fighting.
A pacifist is a peacemaker — even its Latin origins of pax, or "peace" and facere, "to make" show it. If you are a pacifist, you avoid physical confrontations. The beliefs and actions of peacemakers can also be described as pacifist, as in someone whose pacifist beliefs lead him to take part in nonviolent protests against a war.