How do you politely cut off someone who desperately wants to be your friend

Okay, I know this might sound harsh. But I am now 1st year at college and I know that during this time, everyone wants to make friendships. The problem is that this person is someone I don't really like/vibe with. He is basically self-centered and is very clingy. He also posts and share weird posts (mysoginistic and homophobic posts). Cutting him off would be easy if we did not share the same class for a whole semester.