gatekeeper
noun [ C ] uk/ˈɡeɪtˌkiː.pər/ us/ˈɡeɪtˌkiː.pɚ/
看门人，管门人
a person whose job is to open and close a gate and to prevent people entering without permission
（有权决定谁可以得到资源和机会的）看守者
someone who has the power to decide who gets particular resources and opportunities, and who does not
The professors act as gatekeepers who determine which students are admitted into the competetive engineering program. 教授有权决定那些学生可以参加竞争激烈的工程项目。