Twinking is when a player in a game makes a very strong character and gives them really powerful gear and items that make them even stronger than they already are. It's like giving your character a superhero cape that lets them jump even higher and run even faster.
People do this in games to show off to other players and to make sure they are always on top of the game. It's kind of like cheating, but it's not really because you're not hacking the game or breaking any rules.
However, some people don't like it when other players twink because it makes the game unfair and they feel like they can't compete. It's kind of like playing basketball against someone who has a huge height advantage and can dunk the ball without even trying.
So, while twinking can make you really powerful in a game, it can also make the game less fun for other players who don't have the same advantages as you.