Okay kiddo, a cluster bomb is a really big bomb that doesn't just explode in one big blast. Instead, it breaks up into lots and lots of little bombs called submunitions or bomblets. These little bombs then scatter over a wide area to hit lots of different targets all at once.
Now you might be wondering why anyone would want to use a cluster bomb. Well, some people think it can be more effective than just using one big bomb. It can cover a larger area and hit more things, like a group of buildings or a bunch of enemy soldiers.
But here's the problem, sometimes these little bomblets don't explode when they're supposed to. They can stay hidden for years and years, even after the fighting is over. And if someone comes across one by accident, like a farmer working in his field or a child playing outside, they can accidentally set it off and get hurt or killed. People call these unexploded bomblets "duds" and they're a really big danger to people even long after the war is over.
That's why some people think that cluster bombs are dangerous and shouldn't be used anymore. They say that there are other weapons that are just as effective but don't have the same risks for civilians.
So, in a nutshell, a cluster bomb is a big bomb that breaks up into lots of little bombs, and while it can be useful for hitting lots of targets, some people think it's too dangerous because there's a risk the little bomblets won't explode and could hurt people later on.