Does the meaning change if I just say "Don't you turn on me" without "your back"?

Native speaker’s answer
Rebecca
The meaning does change. To "turn on someone" often has the meaning to betray or abandon someone, but in this case we know that is not the case. Voldemort wants to see Harry Potter's face as he dies, which is why he says "don't turn your back on me" here. To "turn your back on someone" often means to ignore or disregard someone. The two differences are slight, but do make a difference here. Ex: Don't turn your back on me! I'm not finished talking with you. Ex: The criminal was quick to turn his back on his partner once he got caught by the police.