ketamine UK /ˈkɛt.ə.mɪn/US /ˈkɛt.əˌmin/ noun1 •A synthetic compound used as a dissociative anesthetic and analgesic drug and also recreationally as a hallucinogen.He was riding high that night, with a brick of Wage's ketamine on its way to Yokohama and the money already in his pocket. — 1984 formsketamines