A pacifist is someone who has strongly held beliefs that war and physical violence are wrong.
Pacifists believe that all disputes should be settled peacefully.
There were pacifists in Britain who refused to fight in World Wars. Many of these ‘conscientious objectors‘ went to prison rather than go against their beliefs - they were prisoners of conscience. They suffered humiliation in prison and after they had been released.
There are different degrees of pacifism - some people are against violence under any circumstances whereas others may disagree with violence but understand that sometimes violence is the least horrible option.