conscientious objector(someone refusing to fight in an armed conflict because of religious or moral principles) noun [UK: ˌkɒn.ʃɪ.ˈen.ʃəs əb.ˈdʒek.tə(r)] [US: ˌkɑːn.ʃi.ˈen.ʃəs əb.ˈdʒek.tər]
refusenik(person who refuses to do something) noun [UK: rɪ.ˈfjuːz.nɪk] [US: rə.ˈfjuːz.nɪk]