The phrase "Holy Willie" is a colloquial term used to describe someone who is excessively religious or pious. Synonyms for this term include "holier-than-thou," "sanctimonious," "self-righteous," "pietistic," "puritanical," "zealot," and "bigoted." These words all convey a sense of someone who is self-righteous or judgmental in their religious beliefs, often to the point of being intolerant of other people's views. While it's important to be devout in one's beliefs, it's just as important to remain open-minded and tolerant of others who may have different perspectives. Using synonyms like these can help convey this message.