authority official permission or approval; "authority for the program was renewed several times"
valuator,
appraiser one who estimates officially the worth or value or quality of things
arbitrator,
arbiter,
umpire 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"
