The Collaborative International Dictionary of English v.0.48:

Kava \Ka"va\, n. [Polynesian.] (Bot.)
   A species of Macropiper (Macropiper methysticum), the
   long pepper, from the root of which an intoxicating beverage
   is made by the Polynesians, by a process of mastication;
   also, the beverage itself. [Written also kawa, kava, and
   ava.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

kava
    n 1: an alcoholic drink made from the aromatic roots of the kava
         shrub [syn: kava, kavakava]

Moby Thesaurus II by Grady Ward, 1.0:

44 Moby Thesaurus words for "kava":
   DET, DMT, LSD, Mary Jane, STP, THC, acid, antidepressant,
   ataractic, diethyltryptamine, dimethyltryptamine, gage, ganja,
   grass, hallucinogen, hash, hashish, hay, hemp, joint, marijuana,
   mescal, mescal bean, mescal button, mescaline, mind-altering drug,
   mind-blowing drug, mind-expanding drug, morning glory seeds,
   peyote, pot, psilocin, psilocybin, psychedelic, psychic energizer,
   psychoactive drug, psychochemical, psychotomimetic, reefer, roach,
   stick, tea, tranquilizer, weed