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]