not involving diplomats (= officials whose job is to represent one country in another, and who usually work in an embassy)

Those forced to leave include non-diplomatic support staff at the foreign embassies, migrant workers, freelance writers, artists, and students. 那些被迫离开的人包括了在外国使馆（工作的）非外交性质的保障人员、外籍务工人员、自由职业作家、艺术家和学生。

Foreign governments can engage in nondiplomatic activity on American soil, but cannot do so via their embassy. 在美国的土地上，外国政府可以参与一些非外交的活动，但是不能以大使馆的名义参与这些活动。

acting in a way that might cause people to be upset, hurt, or annoyed

His colleagues see him as arrogant, non-diplomatic, and pretentious. 在他同事的眼里他是一个傲慢、不懂人情世故、自以为是的人。

If you speak about others in a non-diplomatic way, people will avoid you because they may be the next one to be talked about. 如果你这么不懂人情世故地评价他人，人们会因为（担心）自己可能会成为下一个被你品头论足的对象而对你敬而远之。

Related word: diplomatic