Okay kiddo, do you know what a fender is? It's the part of a car that's attached to the tire and helps protect the car from things that might hit it when it's moving. And a skirt? Well, that's something that people wear to cover up their legs. Now imagine putting a skirt on a fender! That's what a fender skirt is.
A fender skirt is a piece of curved plastic or metal that gets attached to the fender of a car. It covers up the part of the tire that sticks out from the car, making it very aerodynamic and cool looking. It was really popular back in the 1950s and 60s, and cars like Oldsmobiles or Chevys would have them.
Some people think fender skirts are neat because they make cars look more sleek and stylish. Other people don't like them because they can make it hard to change the tire or do other work on the car.
So, basically, a fender skirt is like a fancy dress for a car's fender, and it makes the car look cool but can make it more difficult to fix.