security clearance
noun [ C or U ] uk/sɪˈkjʊə.rɪ.ti ˌklɪə.rəns/ us/sɪˈkjʊr.ə.t̬i ˌklɪr.əns/
保安许可证
official permission for a particular person to enter a building or area or to be given an important job, after making certain that they are not a threat
Some defence jobs require security clearances that are only issued to native-born citizens. 有些国防部门的工作要求申请人持有保安许可证，而这些许可证是只发给本国公民的。