Deletery
Del"e*ter*y\, a. [LL. deleterius: cf. F. d['e]l['e]t[`e]re.] Destructive; poisonous. [Obs.] "Deletery medicines." --Hudibras.Deletery
Del"e*ter*y\, n. That which destroys. [Obs.] They [the Scriptures] are the only deletery of heresies. --Jer. Taylor.