| Noun | 1. | malignancy - (medicine) a malignant state; progressive and resistant to treatment and tending to cause deathcancer cell - a cell that is part of a malignant tumor medical specialty, medicine - the branches of medical science that deal with nonsurgical techniques malignant neoplasm, malignant tumor, metastatic tumor - a tumor that is malignant and tends to spread to other parts of the body |
| 2. | malignancy - quality of being disposed to evil; intense ill will |