法官指定他的叔叔为他的监护人，直到他成年。

The judge appointed his uncle as his custodian until he comes of age.

custodian 是由词根 custody（监护、保管）加上后缀 -ian（表示"从事...的人"）构成的名词，指"监护人"或"保管人"。在法律语境中特指被法院指定负责照顾未成年人或管理其财产的人。