0 the leaves of an Arabian bush, also called khat, that are chewed or made into tea and contain a substance that acts as a stimulant (= a substance that makes the mind or body more active), which is classed as an illegal drug in some countries:
Parts of the khat or qat shrub have been used for centuries as a mild stimulant.
Fresh khat typically is chewed like loose tobacco, and the juice is swallowed.
Cathinone, the key chemical that gives khat its kick, breaks down quickly and vanishes within two to three days.