What does he who throws mud loses ground mean?

This proverb means that if someone tries to damage someone else's reputation or character by spreading false or negative information, they will ultimately end up damaging their own reputation in the process. In other words, when you throw mud at someone, some of it will inevitably land on you. It is a warning against engaging in negative or dishonest behavior, as it can backfire and have unintended consequences. The proverb reminds us that it is better to be honest and have a good reputation than to try to gain an advantage through deception or mudslinging.