N-UNCOUNT
背后說別人的壞話；背后毀謗
If you accuse someone of backbiting, you mean that they say unpleasant or unkind things about someone who is not present, especially in order to stop them doing well at work.
例句
Corporate backbiting is nothing new.
在公司里，背后說人壞話并非什么新鮮事。