Source : Webster's Revised Unabridged Dictionary (1913)

Sicken \Sick"en\, v. t. [imp. & p. p. {Sickened}; p. pr. & vb.
   n. {Sickening}.]
   1. To make sick; to disease.

            Raise this strength, and sicken that to death.
                                                  --Prior.

   2. To make qualmish; to nauseate; to disgust; as, to sicken
      the stomach.

   3. To impair; to weaken. [Obs.] --Shak.

Sicken \Sick"en\, v. i.
   1. To become sick; to fall into disease.

            The judges that sat upon the jail, and those that
            attended, sickened upon it and died.  --Bacon.

   2. To be filled to disgust; to be disgusted or nauseated; to
      be filled with abhorrence or aversion; to be surfeited or
      satiated.

            Mine eyes did sicken at the sight.    --Shak.

Source : WordNet®

sicken
     v 1: cause aversion in; offend the moral sense of; "The
          pornographic pictures sickened us" [syn: {disgust}, {revolt},
           {nauseate}, {churn up}]
     2: get sick; "She fell sick last Friday, and now she is in the
        hospital" [syn: {come down}]
     3: upset and make nauseated; "The smell of the foood turned the
        pregnant woman's stomach"; "The mold ont he food sickened
        the diners" [syn: {nauseate}, {turn one's stomach}]
     4: make sick or ill; "This kind of food sickens me"