Chronic
late Middle English: from French chronique, via Latin from Greek khronikos ‘of time’, from khronos ‘time’.
wiktionary
From chronical, from Old French cronike, from Latin chronicus, from Ancient Greek χρονικός(khronikós, “of time”), from χρόνος(khrónos, “time”).
etymonline
chronic (adj.)
early 15c., cronik, of diseases, "lasting a long time," from Old French chronique and directly 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. Literal sense "pertaining to time" is rare in English. As a popular slang catch-all word for "cannabis," popularized from 1992 by "The Chronic," an album released by rapper Dr. Dre; said to be because it described especially potent marijuana, on the notion of "extreme, severe." Related: Chronical; chronically.
