Chronic definition: constant; habitual; inveterate.. See examples of CHRONIC used in a sentence. Chronic refers to something that continues over an extended period of time. A chronic condition is usually long-lasting and does not easily or quickly go away. CHRONIC meaning: 1. (especially of a disease or something bad) continuing for a long time: 2. very bad: 3…. Learn more. chronic definition: continuing for a long time or constantly recurring. Check meanings, examples, usage tips, pronunciation, domains, and related words. Discover expressions like "something chronic ", " chronic bronchitis", " chronic pleurisy".