The Collaborative International Dictionary of English v.0.48:

katharsis \katharsis\ n.
   purging of emotional tensions; -- usually spelled
   catharsis.

   Syn: catharsis, abreaction.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Catharsis \Ca*thar"sis\, n. [NL., fr. Gr. ?. See Cathartic.]
   (Med.)
   1. A natural or artificial purgation of any passage, as of
      the mouth, bowels, etc.

   2. (Psychotherapy) The process of relieving an abnormal
      excitement by re["e]stablishing the association of the
      emotion with the memory or idea of the event that first
      caused it, and of eliminating it by complete expression
      (called the abreaction).
      [Webster 1913 Suppl.] Cathartic

WordNet (r) 3.0 (2006):

catharsis
    n 1: (psychoanalysis) purging of emotional tensions [syn:
         catharsis, katharsis, abreaction]
    2: purging the body by the use of a cathartic to stimulate
       evacuation of the bowels [syn: catharsis, katharsis,
       purgation]

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "catharsis":
   BM, abreaction, abstersion, acting-out, bloody flux,
   bowdlerization, bowel movement, cleaning, cleansing, crap,
   defecation, dejection, deliverance, detersion, diarrhea, discharge,
   dry cleaning, dysentery, emotional release, evacuation,
   expurgation, flux, freeing, intermission, lientery, loose bowels,
   lustration, motor abreaction, movement, outlet, psychocatharsis,
   psychodrama, purgation, purge, purging, purification, release,
   release therapy, removal, reprieve, respite, runs, shit, shits,
   steam cleaning, stool, surcease, suspension, trots, turistas,
   voidance