反战一词有时是和平主义的同义词，也就是反对在任何冲突中使用军事力量的行为；不过更常用的意思是反对某个特定的国家发动战争。许多激进派主张区分「反战」与「和平」两个词汇。反战激进派认为绝大多数的战争肇因于侵略方，并想办法让侵略方结束战争。

1.反对在任何冲突中使用军事力量的行为。

2.反对某个特定的国家发动战争。

An anti-war movement (also antiwar) is a social movement, usually in opposition to a particular nation's decision to start or carry on an armed conflict, unconditional of a maybe-existing just cause. The term can also refer to pacifism, which is the opposition to all use of military force during conflicts. Many activists distinguish between anti-war movements and peace movements. Anti-war activists work through protest and other grassroots means to attempt to pressure a government (or governments) to put an end to a particular war or conflict.