custodian
noun [ C ] uk/kʌsˈtəʊ.di.ən/ us/kʌsˈtoʊ.di.ən/
formal监护人；监管人；看护人；保管人
a person with responsibility for protecting or taking care of something or keeping something in good condition
the custodian of a museum/castle 博物馆／城堡的看护人
formal（思想或原则的）捍卫者
someone who tries to protect particular ideas or principles
She sees herself as a custodian of the public's morals. 她视自己为公共道德的捍卫者。
US (UK caretaker)看门人，门房；房屋看管人
a person employed to take care of a large building, such as a school, and who deals with the cleaning, repairs, etc.