Umpire

A person to whose sole decision a controversy or question between parties is referred; especially, one chosen to see that the rules of a game, as cricket, baseball, or the like, are strictly observed.

A third person, who is to decide a controversy or question submitted to arbitrators in case of their disagreement.

To decide as umpire; to arbitrate; to settle, as a dispute.

To perform the duties of umpire in or for; as, to umpire a game.

To act as umpire or arbitrator.

someone chosen to judge and decide a disputed issue; "the critic was considered to be an arbiter of modern literature"; "the arbitrator's authority derived from the consent of the disputants"; "an umpire was appointed to settle the tax case"