ma·lig·nant 
/məˈlɪgnənt/ adjective
/məˈlɪgnənt/ adjective [more malignant; most malignant] 1 medical : very serious and dangerous : tending or likely to grow and spread in a rapid and uncontrolled way that can cause death
▪ a malignant [=cancerous] tumor/growth ▪ a highly malignant form of cancer — opposite benign 2 formal : very evil
▪ a powerful and malignant influence
▪ a malignant [=cancerous] tumor/growth ▪ a highly malignant form of cancer — opposite benign
▪ a powerful and malignant influence
— ma·lig·nant·ly adverb
