Attainder

Attainder is when someone is punished without going through a fair trial. Imagine you and your friend have a disagreement, and your friend tells the teacher you did something bad, even though you didn't do it. If the teacher believes your friend without listening to your side of the story, it wouldn't be fair. Attainder is like that, but instead of just missing recess, someone could be punished with a fine, imprisonment, or even lose their property or rights. It's not fair to punish someone without giving them a chance to defend themselves in court. Attainder is not allowed in the law because it goes against the principle of innocent until proven guilty.