The Collaborative International Dictionary of English v.0.48:

Sicken \Sick"en\, v. t. [imp. & p. p. Sickened; p. pr. & vb.
   n. Sickening.]
   1. To make sick; to disease.
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            Raise this strength, and sicken that to death.
                                                  --Prior.
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   2. To make qualmish; to nauseate; to disgust; as, to sicken
      the stomach.
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   3. To impair; to weaken. [Obs.] --Shak.
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