referee
US /ˌref.əˈriː/
UK /ˌref.əˈriː/

1.
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.
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It's a tough game to referee, with so many fast breaks.