同义词

v. drag through the mud，malign，traduce

参考例句

1. Don't badmouth your employer or any of your co-workers to your replacement.
不要向接替你工作的人说上司或者同事的坏话。
2. Don't badmouth your employer to a prospective employer when you go on a job interview.
在你参加新工作的面试时不要向将来可能成为你雇主的人抱怨你的前任上司。
3. According to a recent survey 39% of bosses don't keep their word; 37% don't give credit where it is due; and 27% badmouth those they supervise to coworkers.
根据最近的调查，39%的老板都不信守诺言，37%的老板不对下属的工作给予肯定，27%的老板对下属言语刻薄。

英英解释

v.
  1. speak unfavorably about

网络释义

badmouth somebody
说某人的坏话; 说别人的坏话;