What does cancerous mean?

Cancerous means relating to or characteristic of the disease of cancer. In general, malignant neoplasms, characterized by the proliferation of cells that have escaped from normal control mechanisms with invasion and potential metastasis. Often refers to the cells from tumors of such malignancy which can be called cancer cells. Can be used with either a literal or figurative meaning; e.g., cancerous growth and cancerous ideas respectively.