Popery

Popery is a word that people use to talk about the beliefs, practices, and authority of the Roman Catholic Church. It is often used in a negative or critical way by people who don't agree with or don't like the teachings of the Catholic Church.

In simpler terms, think of it like this: some people don't like the way the Catholic Church operates or what it stands for, so they use the word "popery" to criticize it. It's kind of like using a word that describes a group of people in a negative way, even if it's not a very nice thing to do.