referee

US /ˌref.əˈriː/
UK /ˌref.əˈriː/
"referee" picture
1.

an official who watches a game or match closely to ensure that the rules are adhered to and to arbitrate on matters arising from the play

:
The referee blew the whistle to signal the end of the game.
The player argued with the referee over the foul call.
2.

a person to whom a matter is referred for decision or arbitration

:
The dispute was sent to an independent referee for resolution.
He acted as a referee in the negotiation process.
1.

to act as a referee of (a game or match)

:
He was asked to referee the final match of the tournament.
It's a tough game to referee, with so many fast breaks.