Argumentum ad hominem

Argumentum ad hominem means when someone insults or attacks the person making an argument instead of their actual argument. It's like if you were in an argument with your friend about whether cats or dogs are better pets, and your friend said "you're stupid and don't know anything about pets" instead of explaining why they think dogs are better. This is not a good way to argue, because it doesn't address the actual issue and it's not nice to insult people. It's important to focus on the facts and ideas being discussed, not the person behind them.