Okay, so you know how everyone is different? Some people have different skin colors, speak different languages, and have different religions. Well, there are some people in Ukraine who don't like Jewish people just because they are Jewish. This is called antisemitism.
It's like if you didn't like someone just because they had green eyes. That's not very nice, right? Well, it's the same thing with antisemitism. Some people in Ukraine don't like Jewish people just because of their religion.
This is a big problem because everyone should be treated with kindness and respect, no matter what their religion or background is. We should all be friends and help each other, just like when we play with our friends at school.
Sometimes people who are antisemitic might say mean things about Jewish people, or even hurt them. This is not okay at all. We should always stand up for what is right and defend people who are being treated unfairly.
So, in summary, antisemitism in Ukraine means that some people there don't like Jewish people just because of their religion, and that's not okay. We should always treat everyone with kindness and respect, no matter what they believe or where they come from.