Question

How is backing away from Someone a form of communication

Answer 1

Answer:

I don't think it is. you simply just don't want to be near that person anymore.

Answer 2

Taking this to be body language.
1. Telling someone to stay away. Other could be give you space or them space.
2. You are scared of them so you move away from your hem to avoid getting hurt.
3. You are offended so you back away from the situation.

There are many reasons, it depends on the situation you are in.