late 14c., from Old French narcotique (early 14c.), noun use of adjective, and directly from Medieval Latin narcoticum, from Greek narkotikon, neuter of narkotikos "making stiff or numb," from narkotos, verbal adjective of narcoun "to benumb, make unconscious," from narke "numbness, deadness, stupor, cramp" (also "the electric ray"), perhaps from PIE root *(s)nerq- "to turn, twist." Sense of "any illegal drug" first recorded 1926, American English. Related: Narcotics.
c. 1600, from Middle French narcotique (14c.) or German narkotisch and directly from Medieval Latin narcoticus, from Greek narkotikos (see narcotic (n.)). Related: Narcotical (1580s).