causing or tending to cause sleep.

pertaining to or characterized by sleep or sleepiness; sleepy; drowsy.

something that causes sleep, as a medicine or drug.

adjective

awake , conscious , exciting , invigorating , stimulating

adjective

anesthetic , balmy , calming , deadening , dozy , drowsy , dull , hypnotic , mesmerizing , narcotic , nodding , numbing , opiate , quietening , sedative , slumberous , snoozy , somniferous , somnolent , soothing , tranquilizing , somnifacient , somnific , slumbery , lethargic , opium , sleepy

noun

hypnotic , narcotic , opiate , sedative , somnifacient