回答：是permission。

意思：n. 同意，许可；许可证，书面许可

拓展：mit结尾的动词变名词，admit-admission，emit-emission,limit-limitation，commit-commiment。

例句

①They cannot leave the country without permission.

没有许可他们不得离开这个国家。

②He asked permission to leave the room.

他请求离开房间的许可。

③You are not to leave your station without permission.

未经允许，不得离开岗位。