志愿军

voluntary意思是自愿的、志愿的，如voluntary service(自愿服务)，a volunteer Army(志愿军)。

 义军

... 夜行军 a night march 义军 volunteer Army 英军 British army ...

 义勇军

... 义勇 courageousrighteous and courageous 义勇军 volunteer Army 义勇军进行曲 March of the volunteer Army ...

Professor: What motivation beyond the pay do you think is operating in the case of the all-volunteer army?

教授：你认为，在志愿服役制中，除了工资外，大家参军还有什么动机？

Ming Ng was born in Changbai swing Ju-Bing Joined Ming forces, riding a white boat with trained volunteer army.

明末吴日生在长白荡举兵抗清，用踏白船训练义军。

He argues that an all-volunteer army is unfair because the great majority of those who bear arms are from poorer communities.

他质疑志愿军人招募是不公正的，因为其中绝大部分拿起武器的士兵都是从贫困的社区中来的人。