STIMULANT

[noun] [C]Tourism has acted as a stimulant to the country's economy (= It has made the economy grow).A stimulant is also a substance, such as a drug, which makes the mind or body more active.Caffeine, which is found in coffee and tea, is a mild stimulant.An American athlete has been disqualified from the championship for the use of a banned stimulant.She was found to have taken strychnine, a substance which acts as a stimulant to the central nervous system.