The word 'referee' can be substituted by a few useful synonyms. One such synonym is an 'umpire' who is responsible for monitoring matches and ensuring that the rules are obeyed. Another excellent synonym is a 'judge' who is in control of making crucial decisions in a game or contest. A 'official' or 'officiator' is another synonym that refers to a person who upholds the guidelines and regulations of the game. Finally, a 'arbitrator' is a legal term utilized for a person responsible for settling disputes or conflicts between parties during a game or event. Depending on the context, these synonyms can be used interchangeably and yield the same meaning as the term 'referee'.