Decretalist

A decretalist is a fancy word for someone who studies or writes about church law. This means they look at rules and guidelines made by the church and try to explain them in a way that everyone can understand. They are like a teacher who tells you what you can and can't do, but they do it using special words that only grown-ups might understand. Sometimes people need help understanding what they can and can't do, so decretalists try to make it easier for them.