Sentence:  He is a <WSD>trustee</WSD> for the common good , however feeble the safeguards which the positive or municipal law of property provides against his misuse of that share of the common fund , wisely or unwisely , entrusted to his keeping . 
Meaning of the word marked with <WSD> tags:  a person (or institution) to whom legal title to property is entrusted to use for another's benefit