stim·u·lant 
/ˈstɪmjələnt/ noun
plural stim·u·lants /ˈstɪmjələnt/ noun [count] 1 : something (such as a drug) that makes you more active or gives you more energy
▪ Caffeine is a stimulant. 2 : something that causes more activity : stimulus
▪ The movie was a stimulant to discussion.
▪ Caffeine is a stimulant.
▪ The movie was a stimulant to discussion.
