[1] : The Collaborative International Dictionary of English v.0.48

malicious \mali"cious\, a. of. malicius, f. malicieux, fr. l.
   malitiosus. see malice.
   1. indulging or exercising malice; harboring ill will or
      enmity.
      1913 webster

            i grant him bloody, . . .
            sudden, malicious, smacking of every sin
            that has a name.                      --shak.
      1913 webster

   2. proceeding from hatred or ill will; dictated by malice;
      as, a malicious report; malicious mischief.
      1913 webster

   3. law with wicked or mischievous intentions or motives;
      wrongful and done intentionally without just cause or
      excuse; as, a malicious act.
      1913 webster

   malicious abandonment, the desertion of a wife or husband
      without just cause. --burrill.

   malicious prosecution or malicious arrest law, a wanton
      prosecution or arrest, by regular process in a civil or
      criminal proceeding, without probable cause. --bouvier.
      1913 webster

   syn: ill-disposed; evil-minded; mischievous; envious;
        malevolent; invidious; spiteful; bitter; malignant;
        rancorous; malign.
        1913 webster -- mali"ciously, adv. --
        mali"ciousness, n.
        1913 webster
see also:
malice malicious abandonment malicious prosecution malicious arrest mali"ciously mali"ciousness 

[2] : WordNet (r) 2.0

maliciousness
     n : feeling a need to see others suffer syn: malice, spite,
          spitefulness, venom
see also:
malice spite spitefulness venom 

Maliciousness >> M Words
Maliciousness, definition of term: Maliciousness
maliciousness_pag1.html