'Defamer' definitions:

Definition of 'defamer'

From: WordNet
noun
One who attacks the reputation of another by slander or libel [syn: defamer, maligner, slanderer, vilifier, libeler, backbiter, traducer]

Definition of 'Defamer'

From: GCIDE
  • Defamer \De*fam"er\, n. One who defames; a slanderer; a detractor; a calumniator. [1913 Webster]