0 A malignant tumour (= a group of diseased cells) is one that could cause death. -- maligno
1 (of people, their actions etc) intending, or intended, to do harm -- maligno, malevolo
a malignant remark.
2 (of a tumour/tumor, disease etc) likely to become worse and cause death -- maligno
She died of a malignant tumour.