cancerous
adj.describing cells or growths that are harmful and can spread through the body. It is also used to describe something that is very bad and spreads quickly, like a toxic attitude.
adj.relating to or affected by a malignant growth or tumor. In a figurative sense, it describes something harmful or destructive that spreads uncontrollably within a system or group.
“The doctor removed a cancerous growth from the patient's arm.”
“The lab results confirmed that the tissue was cancerous and required immediate treatment to prevent it from spreading.”
Often used predicatively after linking verbs like 'is' or 'became', or attributively before a noun.
From Middle English cancerous, from Latin cancerōsus, from cancer (“crab; tumor, cancer”) + -ōsus (adjective-forming suffix). By surface analysis, cancer + -ous.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.