throw mud at somebody 泼脏水

“泼脏水”，字面意思“splash dirty water”，泛指对人造谣污蔑，刻意中伤（slander），与英文习语“hurl/throw/sling mud at somebody”意思相近，表示“to say insulting or unfair things about someone, especially to try to damage their reputation”。

例句：

为了诋毁她的名誉，有人不停地往她身上泼脏水。

Someone has kept throwing mud at her in order to vilify her reputation.