soporiferous

Adjective

Synonyms: soporific somniferous somnific hypnogogic hypnagogic narcotic

WordNet 3.0

Adjective (2)

sleep inducingSynonyms: soporific somniferous somnific hypnogogic hypnagogic
inducing mental lethargy“a narcotic speech”Synonyms: narcotic soporific

Webster's Dictionary (GCIDE)

Soporiferous \Sop`o*rif"er*ous\, a. [L. soparifer; sopor a heavy sleep + ferere to bring.] Causing sleep; somniferous; soporific. "Soporiferous medicine." --Swift. [1913 Webster] -- Sop`o*rif"er*ous*ly, adv. -- Sop`o*rif"er*ous*ness, n. [1913 Webster]