mudslinging

音标发音

He's just slinging mud.
他只是在中伤人。
You're slinging mud at me -- that's a pack of lies!
你血口喷人，不讲道理。
《新英汉大辞典》
There's too much mud- slinging by irresponsible journalists.
不负责任的新闻工作者肆意诽谤的事太多了。

So are we to assume that Apple is going to lower itself down from the pulpit, as the mobile innovator of the last decade, and down into the mud slinging and confusion of carrier handset sales and distribution by releasing a bastard iPhone 4?
FORBES: An Old iPhone on Verizon Won't Wow You
He is also trying to avoid mud-slinging in the primary, before November's confrontation with Mr Davis.
ECONOMIST: Maybe, if he stays a liberal Republican
This approach has the same blame-shifting, mud-slinging potential as the debacle at Lloyd's in the 1990s.
ECONOMIST: Professional services

the act of saying insulting or unfair things about someone, especially to try to damage their reputation

If you accuse someone of mudslinging, you are accusing them of making insulting, unfair, and damaging remarks about their opponents.