Okay kiddo, imagine you have a group of people who are very scared of something they don't understand. Maybe they think there are monsters under their bed or ghosts in their house. But instead of being brave and trying to understand what these things really are, they start blaming someone in their village for causing all the trouble.
They say that this person is a witch and that they have magical powers that are making bad things happen. Even though this person is just like everyone else in the village, they start getting treated very badly. People start saying mean things about them, and they might even hurt them or make them leave the village altogether.
This is called a "witch hunt" because people are going crazy trying to find this so-called witch and punish them, even though there's no proof that this person is doing anything wrong. It's like a big game of "let's blame someone else for our problems" and it can be really scary and unfair for the person who's being accused.