defamer
/ˈdɛfˌeɪmər/Definitions
1. noun
A person who spreads false or damaging information about someone, especially through the media.
“The celebrity sued the tabloid for defamation and accused the journalist of being a defamer.”
2. verb
To spread false or damaging information about someone, especially through the media.
“The politician was accused of defaming her opponent with a series of inflammatory statements.”