Main Entry: ma·lig·nant

Pronunciation: \mə-ˈlig-nənt\

Function: adjective

Etymology: Late Latin malignant-, malignans, present participle of malignari

Date: circa 1545

1 a obsolete : malcontent, disaffected b : evil in nature, influence, or effect : injurious c : passionately and relentlessly malevolent : aggressively malicious
2 : tending to produce death or deterioration <malignant malaria>; especially : tending to infiltrate, metastasize, and terminate fatally <a malignant tumor>

— ma·lig·nant·ly adverb