Definition
- C2
To do something secretly and unfairly, without the knowledge or consent of the person affected.
背地里（做不光明的事）
She is always saying bad things about me behind my back.
她总是在我背后说我的坏话。
I can't believe he would do that behind my back.
我无法相信他竟然会在我背后做那种事。
They made decisions without my permission, completely behind my back.
他们未经我的允许就做了决定，完全是在我背后进行的。