What is "stupefacient"

Stupefacient \Stu`pe*fa"cient\, a. [L. stupefaciens, p. pr. of stupefacere to stupefy; stupere to be stupefied + facere to make. Cf. Stupefy.] [Written also stupifacient.] Producing stupefaction; stupefactive. -- n. (Med.) Anything promoting stupefaction; a narcotic.

a. (context medical English) inducing stupor or drowsiness (with a drug such as a narcotic or an anaesthetic) n. (context medical English) a drug that has the above effect