How do you get rid of a bad friend?

I have a friend that ive known for atl east a year, and he has changed more than ever. He used to be a goody good and didn't cuss or dress all dark. Now he does, He has to say ***** or hoe like EVERY OTHER word. He does not know how to dress, Expeically when he is trying to dress like me. He is getting REALLY annoying and her has ruened atleast 3 of my really great friend ships. What should I do!?!?(Btw I know I can't spell.)