Stimulant

Part of speech: noun (n.)

1. That which stimulates, provokes, or excites. His feelings had been exasperated by the constant application of stimulants. Macaulay.

2. 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.

Part of speech: adjective (a.)

1. Serving to stimulate.

2. Produced increased vital action in the organism, or in any of its parts.