Possible meanings are 1) this is simply a way to address a stranger or 2) Jesus is rebuking the man. Your language might have a way of addressing people in either of these ways. Some people do not translate this word at all.
Jesus uses a question to rebuke the man. Alternate translation: "no one appointed me a judge or mediator over you." or "I am not your judge or mediator." (See: [[rc://en/ta/man/translate/figs-rquestion]])