prelate vs high priest

prelate and high priest both are nouns.

Word	Noun	Adjective	Verb	Adverb
prelate	Yes	No	No	No
high priest	Yes	No	No	No

As nouns, prelate and high priest are synonyms defined as:

Other synonyms of prelate include archpriest, hierarch, primate.

prelate (noun)	high priest (noun)
a senior clergyman and dignitary	a senior clergyman and dignitary
	a preeminent authority or major proponent of a movement or doctrine