the GNU version of the Collaborative International Dictionary of English
n. One who maligns.
The Century Dictionary and Cyclopedia
n. One who maligns or speaks malignantly of another; a traducer; a defamer.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. one who attacks the reputation of another by slander or libel
Word Usage
"But it's really my maligner who's a bit creepy and laughable for carrying on as if he's more fair-minded than due process advocates who see right through him."