Stimulant

1. n. An agent which produces a temporary increase of vital activity in the organism, or in any of its parts; — sometimes used without qualification to signify an alcoholic beverage used as a stimulant.
2. a. Serving to stimulate.
3. a. Produced increased vital action in the organism, or in any of its parts.
4. n. That which stimulates, provokes, or excites.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.