1. The quality or state of being inveterate or deeply ingrained: "She never could understand the inveteracy of people's prejudices."
2. The firm establishment by long continuance; firmness or deep-rooted obstinacy of any quality or state acquired by time; such as, the inveteracy of custom, habit, or disease; usually in a bad sense; such as, the inveteracy of errors.
3. Malignity; spitefulness; virulency.