arbitrator vs arbiter

arbitrator and arbiter both are nouns.

Word	Noun	Adjective	Verb	Adverb
arbitrator	Yes	No	No	No
arbiter	Yes	No	No	No

As nouns, arbitrator and arbiter are synonyms defined as:

arbitrator and arbiter: someone chosen to judge and decide a disputed issue

Other synonyms of arbitrator include umpire.

arbitrator (noun)	arbiter (noun)
someone chosen to judge and decide a disputed issue	someone chosen to judge and decide a disputed issue
	someone with the power to settle matters at will