appoint 通常指不经过选择的官方委任。
designate 书面用语，侧重当权者或机构的选拔或任命，有时含强行指定的意味。
assign 常指给一群人或个人分配、分派、指派或委派任务。
name 普通用词，着重任命的结果，而不是过程。
nominate 通常指为某一公职选择候选人，并将其提交给有决定权的人作最后决定。
参考例句
1. She designated the place where we were to meet. 她指定了我们将会面的地点。
2. Your instructor will designate the RCS number to obtain status information for this exercise. 您的指导者将指定这个练习用来获得状态信息的RCS号。
3. Easy labor dispute cases, the Arbitration Commission may designate an arbitrator to deal with. 简单劳动争议案件，仲裁委员会可以指定一名仲裁员处理。
英英解释
v.
1. assign a name or title to
2. give an assignment to (a person) to a post, or assign a task to (a person)
3. decree or designate beforehand
4. design or destine adj.
1. appointed but not yet installed in office
