1911 Encyclopædia Britannica/Kief

KIEF, Kef or Keif (a colloquial form of the Arabic kaif, pleasure or enjoyment), the state of drowsy contentment produced by the use of narcotics. To “do kef,” or to “make kef,” is to pass the time in such a state. The word is used in northern Africa, especially in Morocco, for the drug used for the purpose.