the.com/malignancy

means A malignancy is a cancerous growth that invades surrounding tissue and can spread to other parts of the body, rather than staying put and harmless.

from From Latin malignus, 'evil-disposed' or 'spiteful,' itself built from male ('badly') plus a root shared with gignere ('to beget, produce') — so literally something like 'badly born' or 'born of ill will.' The word lived for centuries as a general term for malice or harmful influence — a malignant star, a malignant tongue — before medicine narrowed it, by around the 16th–17th century, to describe diseases and tumors that behave with that same old sense of active, spreading ill intent rather than lying dormant.