The Collaborative International Dictionary of English v.0.48:

Calumny \Cal"um*ny\, n.; pl. Calumnies. [L. calumnia, fr.
   calvi to devise tricks, deceive; cf. F. calomnie. Cf.
   Challenge, n.]
   False accusation of a crime or offense, maliciously made or
   reported, to the injury of another; malicious
   misrepresentation; slander; detraction. "Infamous calumnies."
   --Motley.
   [1913 Webster]

         Be thou as chaste as ice, as pure as snow, thou shalt
         not escape calumny.                      --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

calumny
    n 1: a false accusation of an offense or a malicious
         misrepresentation of someone's words or actions [syn:
         defamation, calumny, calumniation, obloquy,
         traducement, hatchet job]
    2: an abusive attack on a person's character or good name [syn:
       aspersion, calumny, slander, defamation,
       denigration]

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "calumny":
   abuse, animadversion, backbiting, backstabbing, belittlement,
   bitchiness, calumniation, cattiness, contumely, defamation,
   depreciation, disparagement, invective, libel, obloquy, opprobrium,
   reflection, revilement, scandal, scurrility, slander, stricture,
   tale, traducement, vilification, vituperation