The Collaborative International Dictionary of English v.0.48:

Punishment \Pun"ish*ment\, n.
   1. The act of punishing.
      [1913 Webster]

   2. Any pain, suffering, or loss inflicted on a person because
      of a crime or offense.
      [1913 Webster]

            I never gave them condign punishment. --Shak.
      [1913 Webster]

            The rewards and punishments of another life.
                                                  --Locke.
      [1913 Webster]

   3. (Law) A penalty inflicted by a court of justice on a
      convicted offender as a just retribution, and incidentally
      for the purposes of reformation and prevention.
      [1913 Webster]

   4. Severe, rough, or disastrous treatment. [Colloq. or Slang]
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

punishment
    n 1: the act of punishing [syn: punishment, penalty,
         penalization, penalisation]