1. arbiter, supreme authority

someone with the power to settle matters at will

Example Sentences:
'she was the final arbiter on all matters of fashion'

Synonyms

• supreme authority

2. arbiter, arbitrator, umpire

someone chosen to judge and decide a disputed issue

Example Sentences:
'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'

Synonyms

• arbitrator
• umpire