Calvin Klein special noun a mixture of cocaine and the recreational drug ketamine US A back formation from the initials.
Users pay from $20 to $40 per dose, or “bump,” usually to be mixed with heroin or cocaine and snorted (the coke/ketamine combo is called CK or the “Calvin Kelin Special”)[.] — TheRecord[BergenCounty, NewJersey], p. A1, 5 December 1995