"A drug with properties and effects similar to a known hallucinogen or narcotic but having a slightly altered chemical structure, especially such a drug created in order to evade restrictions against
illegal substances."
(Answers.com)
A synthetic chemical (Often produced by a high-tech lab) the purpose of which is to produce a reliable state of
intoxication (As opposed to plant-based inebrients, whos effects may vary greatly from one
individual to another)