a person who believes in acting independently, without involving another group or country

They are both, in different ways, outspoken unilateralists. 尽管做法不尽相同，他们都是直言不讳的单边主义者。

a person who believes in getting rid of your country's nuclear weapons without first waiting for other countries to do the same

He is a left-winger and apparently still a committed unilateralist. 他是一个左翼分子，显然还是一个坚定的单方面销毁核武器者。

of or relating to unilateralism (= the process or fact of deciding a policy or action without involving another group or country)

There's a return to a more unilateralist worldview. 一种更加单边主义的世界观正在回归。

He has aggressively criticized the president for his unilateralist approach to the world. 他强烈批评总统对世界采取的单边主义做法。