adj.1 a (of a disease) very virulent or infectious (malignant cholera). b (of a tumour) tending to invade normal tissue and recur after removal; cancerous.
2 harmful; feeling or showing intense ill will.
Phrases and idioms:
malignant pustule a form of anthrax.
Derivatives:
malignancy n. (pl. -ies). malignantly adv.
Etymology: LL malignare (as MALIGN)