Veneficial \Ven`e*fi"cial\, Veneficious \Ven`e*fi"cious\, a. Acting by poison; used in poisoning or in sorcery. [Obs.] "An old veneficious practice." --Sir T. Browne. -- {Ven`e*fi"cious*ly}, adv. [Obs.] [1913 Webster]