hierarch vs archpriest

hierarch and archpriest both are nouns.

Word	Noun	Adjective	Verb	Adverb
hierarch	Yes	No	No	No
archpriest	Yes	No	No	No

As nouns, hierarch and archpriest are synonyms defined as:

Other synonyms of hierarch include high priest, prelate, primate.

hierarch (noun)	archpriest (noun)
a senior clergyman and dignitary	a senior clergyman and dignitary
a person who holds a high position in a hierarchy