talk behind somebody's back

I had the strange looks then, the people talking behind my back.

"I have heard that people talk about me behind my back."

It's not that anyone was cruel or talking behind my back.

You and she have been talking about me behind my back?

But that doesn't prevent people from talking behind your back.

Remember that if he ever starts talking to you behind my back.

Someone had talked behind his back, that much was certain.

But I wouldn't ask you to talk about him behind his back.

Later, he'd had an uneasy feeling that people were talking about him behind his back.

"So you two have been talking about me behind my back'" she demanded.