What is the definition or description of: malignant?

Invasive cancer. : The term malignant can be used in several medical contexts, but is primarily used to describe cancers. More dangerous and disorderly than the benign growth of cells, malignant cells have developed genetic changes that can allow it to invade other tissues in an unregulated way. These tumors can later spread, or metastasize, to other parts of the body and continue invading normal tissue.

Malignant: The term “malignant” is mainly used in the context of cancer, but can also be used to describe a condition that can be acutely damaging to the body, such as “malignant hypertension”.