Source : Webster's Revised Unabridged Dictionary (1913)

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.]
   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.

   2. To injure or kill by poison; to administer poison to.

            If you poison us, do we not die ?     --Shak.

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

            Whispering tongues can poison truth.  --Coleridge.

Source : WordNet®

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