Narcotic
WordNet
adjective
(1) Inducing mental lethargy
"A narcotic speech"
(2) Inducing stupor or narcosis
"Narcotic drugs"
(3) Of or relating to or designating narcotics
"Narcotic addicts"
"Narcotic stupor"
noun
(4) A drug that produces numbness or stupor; often taken for pleasure or to reduce pain; extensive use can lead to addiction