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. Jealousy was assigned as motive for the crime. 把这一犯罪行为的动机归因于忌妒。
2. Assign variables to objects in the template. 分配的对象变量在模板中。
3. You can assign seats for the other 4 as your own wish. 您能分配位子为其它4个作为您自己的愿望。
英英解释
v.
1. give an assignment to (a person) to a post, or assign a task to (a person)
2. give out or allot
3. attribute or credit to
4. select something or someone for a specific purpose
5. attribute or give
6. make undue claims to having
7. transfer one's right to
8. decide as to where something belongs in a scheme
