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 ]