Banning is saying, with some force, that a thing must not be done, seen, used, sold, or shown. A school can be banning phones in class. A city can be banning smoking indoors. A website can be banning a user who broke the rules. The word is the -ing form of ban, and you will also meet it as a name for the act itself: “the banning of that book” means the decision that stopped people using it.

It sounds more official than “not allowed.” Parents “don’t let you”; governments, schools, and platforms “ban.” Though actually, everyday people now say it about small things too — “they’re banning that joke on this app” may only mean the app will hide it, not that a law was passed. The tidy picture is a big rule; the messy truth is that banning now covers anything from a court order to a group chat kicking someone out.

You ban an action or a thing, and you can also ban a person from a place (“banned from the club”). You do not “ban a person” in the sense of making them disappear; you stop them from doing something or going somewhere.