a person who believes in pacifism or is opposed to war or to violence of any kind.

a person whose personal belief in pacifism causes him or her to refuse being drafted into military service. Compare conscientious objector.

pacifistic.

noun

antiwar demonstrator , conscientious objector , dove , passive resister , peacemaker , peacemonger , peacenik , appeaser , flower child

adjective

irenic , pacific , pacifical , pacifistic , peaceful