Libri prohibiti means "prohibited books". Sometimes there are books that people think are a bad influence or have bad ideas, and they don't want other people to read them. So they make a list of these books and say that nobody is allowed to read them. These books are called "libri prohibiti". It's kind of like when your parents say you can't watch a scary movie because they think it will give you nightmares. But instead of just your parents making the rule, it's a whole group of people. Sometimes these books are banned by government, church, or cultural groups. However, it's important to remember that even if a book is on the "libri prohibiti" list, it doesn't mean that it's necessarily bad or wrong to read it. Sometimes reading these forbidden books can help people learn new things or think about things in a different way. It's always important to read with an open mind and form your own opinions.