Imagine you have a house with many windows. Now, one day, someone breaks one of your windows. This is called a broken window.
If you don't fix the broken window, then other people might think it's okay to break more windows. It can also make your house look bad and let in dirt, dust, and cold air, which is not a good thing.
So to fix the broken window, you need to call a special person called a window repairman. They come to your house and replace the broken glass with a brand new one, making your window look good as new!
This is called fixing a broken window, and it's important because it helps keep your home safe and clean.