Shunning is when people stop talking to and spending time with someone on purpose. It's like when you're playing with your friends and then suddenly they say they don't want to play with you anymore and they leave. But shunning is much more serious and it can go on for a long time.
It happens in some families and communities when someone breaks a rule or does something that people don't like. Instead of talking things out and trying to understand each other, they just ignore the person and act like they don't exist. That means they don't let them come to family gatherings or events and don't talk to them on the phone or online.
It can be very hurtful and make people feel sad and alone. But it's important to remember that it's not okay to treat people like this. We should always try to understand and communicate with each other, even when we disagree or make mistakes.