Gamekeeper is someone who takes care of wildlife and game animals in a forest or on a large piece of land. Imagine you have a big garden with many tomato plants, and you want to make sure they are safe, and nobody comes and takes them away. That's why you put a fence around the garden to protect it. A gamekeeper is like a caretaker of the forest, who makes sure all the animals living there are safe and healthy.
Gamekeepers are like animal doctors, who feed and take care of the animals living on the forest grounds. They also make sure that hunters come and hunt only the animals that are healthy and the ones there are more of. This way, there would always be enough animals left for the future, and we won't run out of them.
Just like you have to clean up your room regularly, gamekeepers clean up the woods and take care of the trees and the water so that animals can have a safe and healthy environment to live in.
In summary, a gamekeeper is someone who takes care of wildlife and makes sure that animals are healthy and safe in the forest or on a large piece of land.