What is Chronic ?
Chronic is (adj) 1. (of illness or pain) serious and continuing for a long time She has chronic bronchitis. Chronic asthma sufferers need to use special drugs. Compare acute 2. referring to someone who does a particular activity, especially a harmful one, often a chronic smoker 3. very bad (informal.) We have a chronic shortage of skilled staff.
source: Easier English, Student Dictionary Upper Intermediate Level