Show that you don't want to know him, don't want to have anything to do with him, but still stick to you. How does a malicious person get rid of himself?

The most effective way for such a persistent person is to ignore him. Turn a blind eye to him and don't respond to all his actions. Including avoiding him, not talking, not looking at him, and having no expression on him. As long as you hold on, it will gradually cool down. After all, one link is linked with another, so as long as you insist on treating him like air, he will know his own interests over time. It's just a matter of time. In addition, you should also consider whether he is an extreme person. If he tends to go to extremes, you'd better try to avoid him completely and try not to meet him. As for him spying on you with a trumpet. You just have to turn a blind eye. As long as you insist on being unmoved, he will shrink back.