The phrase "pagan priests" refers to religious leaders or clergy who practice and follow ancient polytheistic or non-Christian religions. Full definition
And remember the context in which Paul was exposed to homosexuality... as he was writing Romans, he had just returned from one of his missionary journeys where he witnessed pagan priests and priestesses engaging in some odd sexual behaviors — including castrating themselves, carrying on drunken sexual orgies, and even having sex with young temple prostitutes (male and female)-- all to honor the gods of sex and pleasure. (nakedpastor.com)
It kinda became their god, and they interpret what this god says pretty much exactly the same way ancient pagan priests interpreted what their stone gods said. (religion.blogs.cnn.com)
It is strange to see us all sitting together at the sacred meal — master breaking bread with his slave, a Jew sharing a joke with a former pagan priest, a husband pouring wine for his wife, a zealot debating politics with a tax collector — but this is what makes us different; it's what makes us Christians. (rachelheldevans.com)