Summarize the following:
Simply avoiding places where he goes or hangs out, if possible, will send him a message. If he never sees you, he will likely stop thinking about you or trying to pursue you as much. Get on your social media accounts like Facebook, Twitter, Instagram, and Snapchat, and block him from seeing your posts and photos and interacting with you. All of the major social network sites and apps have easy ways of un-friending and blocking any user you want. Try asking his friends or using what you already know about what he doesn't like to make yourself less desirable to him. If he hates a certain sports team, start talking to him about only that team. If the sound of chewing gum or humming drives him nuts, start doing those things around him. An out-there move to try is acting the complete opposite and give him a lot of attention. Be completely overbearing and demanding of his attention, even acting like you're already in a relationship. Take it to a ridiculous level if you need to. It may be that he just wanted the attention from you and will leave you alone once he gets it, or he will be so turned off by your over-attentiveness that he'll back off.
Avoid him. Block him on social networks. Find out what he dislikes and start doing it. Use reverse psychology.