arbitrar

adv. arbitrarily, wantonly; in a tyrannical manner

adj. arbitrary, wanton, reckless, uncontrolled, unrestricted; unreasonable

v. arbitrate, act as a mediator in a dispute; serve as a judge

v. arbitrate, award, referee

arbitrary
arbitrarily

= officiate, referee.
Ex: Umpires and referees officiate at sporting events, making sure the rules and regulations of the game are followed.
Ex: Many had been refereeing for many years, so it is perhaps not surprising that most of them thought things had not changed for the better.