n.

1. 权，权力；职权[U][（+for）][+to-v]
   Who gave you authority to do this?

   谁给你权力这样做的？

2. 当权者，管理机构[C]
3. 官方，当局[P]
   The authorities did not interfere with us.

   当局不干涉我们。

4. 权威人士；专家，泰斗[C][（+on）]
   He is an authority on international law.

   他是一位国际法权威。

5. 权威，威信，影响力[U]
6. 授权书[S]
7. 依据，来源[U]
8. 【律】判例

n.

1. the power or right to give orders and enforce obedience.
2. a person or organization exerting control in a political or administrative sphere.
3. the power to influence others based on recognized knowledge or expertise.
   ▸an authoritative person, book, or other source.