traducer

noun

1. One who traduces; one who maligns another by making malicious and false or defamatory statements.

   “I greatly mistrust that the Bohemian on our shores is a much-abused man. To his traducer, who casts up anarchism against him, he replies that the last census (1880) shows his people to have the fewest criminals of all in proportion to numbers.”

   “In short, Mr. Price defended the country against its traducers, saying that, "so far from the Territory deserving the title of White Elephant, it was a credit to South Australia, and a valuable portion of her possessions."”