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

malignance \malig"nance\, malignancy \malig"nancy\, n. see
   malignant.
   1. the state or quality of being malignant; extreme
      malevolence; bitter enmity; malice; disposition toward
      evil; intense ill will; as, malignancy of heart.
      1913 webster

   2. unfavorableness; evil nature.
      1913 webster

            the malignancy of my fate might perhaps distemner
            yours.                                --shak.
      1913 webster

   3. med. virulence; tendency to a fatal issue; as, the
      malignancy of an ulcer or of a fever.
      1913 webster

   4. hence: med. a cancerous tumor that is spreading beyond
      the point of origin.

   syn: malignant tumor, malignant neoplasm, metastatic tumor.
        wordnet 1.5

   5. the state of being a malignant.
      1913 webster
see also:
malignant 

[2] : WordNet (r) 2.0

malignancy
     n 1: medicine a malignant state; progressive and resistant to
          treatment and tending to cause death syn: malignance
     2: quality of being disposed to evil; intense ill will syn: malignity,
         malignance ant: benignity, benignity
see also:
malignance malignity benignity 

[3] : Moby Thesaurus II by Grady Ward, 1.0

56 moby thesaurus words for "malignancy":
   balefulness, banefulness, bitchiness, communicability,
   contagiousness, cussedness, deadliness, despite, destructiveness,
   detrimentalness, devilment, devilry, deviltry, evil intent,
   fatality, grudge, harmfulness, hatefulness, hurtfulness, ill will,
   infectiousness, infectivity, iniquitousness, injuriousness,
   invidiousness, lethality, maleficence, malevolence, malice,
   malice aforethought, malice prepense, maliciousness, malignance,
   malignity, meanness, mischievousness, mortality, nastiness,
   noisomeness, noxiousness, ominousness, orneriness, perniciousness,
   poison, poisonousness, spite, spitefulness, spleen, toxicity,
   unhealthiness, venom, venomousness, viciousness, virulence,
   virulency, wickedness

Malignancy >> M Words
Malignancy, definition of term: Malignancy
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