The Collaborative International Dictionary of English v.0.48:

Constipation \Con`sti*pa"tion\, n. [L. constipatio a crowding
   together: cf. F. constipation.]
   1. Act of crowding anything into a less compass, or the state
      of being crowded or pressed together; condensation. [Obs.]
      [1913 Webster]

            Fullness of matter, or a pretty close constipation .
            . . of its particles.                 --Boyle.
      [1913 Webster]

   2. A state of the bowels in which the evacuations are
      infrequent and difficult, or the intestines become filled
      with hardened f[ae]ces; costiveness.
      [1913 Webster]

WordNet (r) 3.0 (2006):

constipation
    n 1: irregular and infrequent or difficult evacuation of the
         bowels; can be a symptom of intestinal obstruction or
         diverticulitis [syn: constipation, irregularity]
    2: the act of making something futile and useless (as by
       routine) [syn: stultification, constipation,
       impairment, deadening]

Moby Thesaurus II by Grady Ward, 1.0:

113 Moby Thesaurus words for "constipation":
   abscess, ague, anemia, ankylosis, anoxia, apnea, asphyxiation,
   asthma, ataxia, atrophy, backache, bar, barrier, blank wall,
   bleeding, blennorhea, blind alley, blind gut, block, blockade,
   blockage, bottleneck, cachexia, cachexy, cardialgia, cecum, chill,
   chills, choking, choking off, cholera morbus, clog, colic,
   congestion, convulsion, costiveness, coughing, cul-de-sac,
   cyanosis, dead end, diarrhea, dizziness, dropsy, dysentery,
   dyspepsia, dyspnea, edema, emaciation, embolism, embolus, fainting,
   fatigue, fever, fibrillation, flux, gorge, gripe, gripes, growth,
   heartburn, hemorrhage, high blood pressure, hydrops, hypertension,
   hypotension, icterus, impasse, impediment, indigestion, infarct,
   infarction, inflammation, insomnia, irregularity, itching, jam,
   jaundice, labored breathing, lientery, low blood pressure, lumbago,
   marasmus, nasal discharge, nausea, necrosis, obstacle, obstipation,
   obstruction, pain, paralysis, pruritus, pyrosis, rash, rheum,
   sclerosis, sealing off, seizure, shock, skin eruption, sneezing,
   sore, spasm, stop, stoppage, strangulation, tabes, tachycardia,
   trots, tumor, upset stomach, vertigo, vomiting, wasting