bad-mouth
口语·表示背后说坏话或诋毁
例句
She always bad-mouths her coworkers behind their backs, which is really unprofessional.
典故来源
源自非洲裔美国英语，bad（坏）与mouth（嘴）组合，字面意思为“坏嘴”，指用恶言诋毁他人。