Whether it’s a bike, an old computer, or a tennis stadium, when you refurbish something you clean it up and make it look or perform better.
When you refurbish something, you generally keep the structure the same but improve its looks and possibly its functionality. For example, if you renovate a room you may make it "new again" with structural changes, such as tearing down walls and altering its original design. If you refurbish it, however, you will most likely focus on making it look better with cosmetic changes, such as painting it. The word refurbish is also often used to describe secondhand technology that has been rebuilt to restore function by replacing a component that has failed.