Sladdbarn is a Swedish word that means "drift child". Imagine you are playing with toy cars on a track, and you want them to go as fast as possible, so you make them slide and drift around the corners. Sladdbarn is like that, but with real cars on the roads.
Sometimes, people who drive cars like to go really fast and make their cars slide around the corners just like toy cars. They might even make their cars "drift" on purpose, which means the back wheels of the car go sideways while the front wheels keep going forward.
But driving like sladdbarn is very dangerous because it can cause accidents and hurt people. That's why it's important to always drive safely and follow the rules of the road.