one who attacks the reputation of another by slander or libel
- She is nothing but a backbiter.
- Besides, he's a bit of a backbiter, and he'd give us a bad name and make things awkward for us if we tried to force something out of him
- “Hold your tongue, backbiter,” said Dolgorukov. “It's not true, there are two Russians: Miloradovitch and Dohturov, and there would have been a third, Count Araktcheev, but for his weak nerves.”