A rebuttal is a response that argues against or disproves what someone else has said. When you offer a rebuttal, you explain why the other person's argument is wrong and back up your position with reasons and evidence.

In a debate, after one side presents their case, the other side gets to make a rebuttal. If your friend argues that your school should eliminate homework and you respond by explaining why practice outside of class helps students learn, you're making a rebuttal. If a scientist proposes a theory and another scientist points out flaws in the research, that's a rebuttal too.

You don't need to be in court to use this word. Any time someone makes a claim and you respond with a reasoned argument showing why they're mistaken, you're making a rebuttal. The key is that a rebuttal builds a counter-argument with logic and facts. A good rebuttal acknowledges what the other person said and then systematically shows why a different conclusion makes more sense.