Webster's Revised Unabridged Dictionary · 1913

Malignance

Malignance , noun

[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.
2.
Unfavorableness; evil nature.
The malignancy of my fate might perhaps distemner yours. — Shakespeare
3.
(Medicine) Virulence; tendency to a fatal issue; as, the malignancy of an ulcer or of a fever.
4.
(Medicine) A cancerous tumor that is spreading beyond the point of origin.
5.
The state of being a malignant.

Also: Malignancy