pontifex vs priest

pontifex and priest both are nouns.

Word	Noun	Adjective	Verb	Adverb
pontifex	Yes	No	No	No
priest	Yes	No	No	No

As nouns, priest is a hypernym of pontifex; that is, priest is a word with a broader meaning than pontifex:

pontifex: a member of the highest council of priests in ancient Rome
priest: a clergyman in Christian churches who has the authority to perform or administer various religious rites; one of the Holy Orders

pontifex (noun)	priest (noun)
a member of the highest council of priests in ancient Rome	a clergyman in Christian churches who has the authority to perform or administer various religious rites; one of the Holy Orders
	a person who performs religious duties and ceremonies in a non-Christian religion