Lethal

lethal
    adj 1: of an instrument of certain death; "deadly poisons";
           "lethal weapon"; "a lethal injection" [syn: {deadly},
           {lethal}]
    

Lethal \Leth"al\ (l[e^]th"[a^]l), n. [Lauric + ether + alcohol.]
   (Chem.)
   One of the higher alcohols of the paraffine series obtained
   from spermaceti as a white crystalline solid. It is so called
   because it occurs in the ethereal salt of lauric acid.
   [1913 Webster]
    

Lethal \Le"thal\ (l[=e]"thal), a. [L. lethalis, letalis, fr.
   lethum, letum, death: cf. F. l['e]thal.]
   Deadly; mortal; fatal. "The lethal blow." --W. Richardson. --
   {Le"thal*ly}, adv.
   [1913 Webster]
    

49 Moby Thesaurus words for "lethal":
      baleful, baneful, brutal, corroding, corrosive, corrupting,
      corruptive, counterproductive, damaging, deadly, death-bringing,
      deathful, deathly, deleterious, destructive, detrimental,
      disadvantageous, disserviceable, distressing, fatal, feral,
      harmful, hurtful, injurious, internecine, killing, malefic,
      malevolent, malign, malignant, mischievous, mortal, noisome,
      noxious, ominous, pernicious, pestilent, pestilential, poisonous,
      prejudicial, savage, scatheful, toxic, venenate, veneniferous,
      venenous, venomous, vicious, virulent