Reputation is how people think about you. It's what people say about you when you're not around. It's based on the things you do or don't do. If you do nice things and make good choices, people will think of you as someone who is trustworthy and nice. If you do bad things or make bad choices, people will think you are not trustworthy or a bad person. Your reputation is important because it lets people know what kind of person you are.