poisonous

from WordNet (r) 3.0 (2006)

poisonous
    adj 1: having the qualities or effects of a poison [syn:
           {poisonous}, {toxicant}]
    2: not safe to eat
    3: marked by deep ill will; deliberately harmful; "poisonous
       hate"; "venomous criticism"; "vicious gossip" [syn:
       {poisonous}, {venomous}, {vicious}]

from 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]

from Moby Thesaurus II by Grady Ward, 1.0

90 Moby Thesaurus words for "poisonous":
      bad, baleful, baneful, barfy, brackish, catching, cloying,
      communicable, contagious, corroding, corrosive, corrupting,
      corruptive, counterproductive, damaging, dangerous, deadly,
      defamatory, deleterious, destructive, detrimental, diabolical,
      disadvantageous, disserviceable, distressing, envenomed, evil,
      fatal, fetid, foul, fulsome, harmful, high, hurtful, icky,
      infectious, infective, injurious, lethal, maggoty, malefic,
      malevolent, malicious, malign, malignant, mawkish, mephitic,
      miasmal, miasmatic, miasmic, mischievous, mortal, nasty, nauseant,
      nauseating, nauseous, noisome, noxious, offensive, ominous,
      overripe, pernicious, pestiferous, pestilent, pestilential, poison,
      prejudicial, rancid, rank, rebarbative, rotten, scatheful, septic,
      sickening, slanderous, spoiled, stinking, toxic, toxicant,
      toxiferous, venenate, veneniferous, venenous, venomous, vicious,
      vile, virulent, vomity, weevily, yucky