GNU Collaborative International Dictionary of English

Found one definition 

  1.       

    { Malignance , Malignancy , } 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