What is the X in X-mas?
early 15c., of diseases, "lasting a long time," from Middle French chronique, from Latin chronicus, from Greek khronikos "of time, concerning time," from khronos "time" (see chrono-). Vague disapproving sense (from 17c.) is from association with diseases and later addictions.
chronic chron·ic (krŏn'ĭk)
Of long duration. Used of a disease of slow progress and long continuance.
Relating to an illness or medical condition that is characterized by long duration or frequent recurrence. Diabetes and hypertension are chronic diseases. Compare acute.
Marijuana; pot: Smoking a spliff of high-octane chronic (1990s+)