The Collaborative International Dictionary of English v.0.48:

Poison \Poi"son\, v. t. [imp. & p. p. Poisoned; p. pr. & vb.
   n. Poisoning.] [Cf. OF. poisonner, F. empoissoner, L.
   potionare to give to drink. See Poison, n.]
   [1913 Webster]
   1. To put poison upon or into; to infect with poison; as, to
      poison an arrow; to poison food or drink. "The ingredients
      of our poisoned chalice." --Shak.
      [1913 Webster]

   2. To injure or kill by poison; to administer poison to.
      [1913 Webster]

            If you poison us, do we not die ?     --Shak.
      [1913 Webster]

   3. To taint; to corrupt; to vitiate; as, vice poisons
      happiness; slander poisoned his mind.
      [1913 Webster]

            Whispering tongues can poison truth.  --Coleridge.
      [1913 Webster]

WordNet (r) 3.0 (2006):

poisoning
    n 1: the physiological state produced by a poison or other toxic
         substance [syn: poisoning, toxic condition,
         intoxication]
    2: the act of giving poison to a person or animal with the
       intent to kill

Moby Thesaurus II by Grady Ward, 1.0:

83 Moby Thesaurus words for "poisoning":
   adulteration, autointoxication, bane, befouling, beheading, blood,
   blood poisoning, bloodletting, bloodshed, braining, burning,
   capital punishment, contamination, corruption, crucifixion,
   dealing death, decapitation, decollation, defenestration,
   defilement, destruction, destruction of life, dispatch,
   electrocution, envenoming, ergotism, euthanasia, execution,
   extermination, festering, flow of blood, food poisoning, fouling,
   fusillade, garrote, gassing, gore, hanging, hemlock, immolation,
   infection, intoxication, judicial murder, kill, killing,
   lapidation, martyrdom, martyrization, mercy killing, milk sickness,
   misuse, necktie party, perversion, pollution, prostitution,
   ptomaine poisoning, pyemia, ritual killing, ritual murder,
   sacrifice, sepsis, septic poisoning, septicemia, septicopyemia,
   shooting, slaughter, slaying, stoning, strangling, strangulation,
   suppuration, taking of life, the ax, the block, the chair,
   the gallows, the gas chamber, the guillotine, the hot seat,
   the rope, toxemia, venenation, vitiation