prelate vs hierarch

prelate and hierarch both are nouns.

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

As nouns, prelate and hierarch are synonyms defined as:

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

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