The Collaborative International Dictionary of English v.0.48:
Poisonous \Poi"son*ous\, a. Having the qualities or effects of poison; venomous; baneful; corrupting; noxious. --Shak. -- Poi"son*ous*ly, adv. -- Poi"son*ous*ness, n. [1913 Webster]WordNet (r) 3.0 (2006):
poisonously adv 1: in a very malevolent manner [syn: poisonously, venomously]