Definition
Cankerous describes something affected by or resembling a canker. A canker is an ulcerous sore, often found in the mouth, or a disease that destroys tissue, especially in plants. Think of it as a persistent, irritating problem that eats away at something. It's more severe than a minor inconvenience; it suggests a deep-seated, destructive force. It can be both a physical ailment or a figurative problem that festers and grows.