ˈɑːbɪtə(ɹ) ˈʌm.paɪ.ə(ɹ) 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 someone with the power to settle matters at will she was the final arbiter on all matters of fashion