The Collaborative International Dictionary of English v.0.48:

Colitis \Co*li"tis\, n. [NL., fr. Gr. ? + -itis.] (Med.)
   An inflammation of the large intestine, esp. of its mucous
   membrane; colonitis.
   [1913 Webster]

WordNet (r) 3.0 (2006):

colitis
    n 1: inflammation of the colon [syn: colitis, inflammatory
         bowel disease]

Moby Thesaurus II by Grady Ward, 1.0:

144 Moby Thesaurus words for "colitis":
   abdominal hernia, adenoiditis, adrenitis, appendicitis, arteritis,
   arthritis deformans, arthritis fungosa, arthritis pauperum,
   atrophic arthritis, atrophic inflammation, blennorrhagic arthritis,
   brain fever, bronchitis, bunion, bursitis, capillaritis, carditis,
   catarrh, catarrhal inflammation, cerebellitis, cerebral meningitis,
   cerebritis, cerebrospinal meningitis, chronic infectious arthritis,
   chronic inflammation, cirrhotic inflammation, climactic arthritis,
   clitoritis, collagen disease, conjunctivitis, cystitis,
   degenerative arthritis, diffuse inflammation, diverticulitis,
   diverticulosis, duodenal ulcer, duodenitis, encephalitis,
   endocarditis, enteritis, equine encephalomyelitis, esophagal ulcer,
   esophagitis, exudative inflammation, fibroid inflammation,
   focal inflammation, gastritis, gingivitis, glossitis,
   gonococcal arthritis, gonorrheal arthritis, gonorrheal rheumatism,
   gout, gouty arthritis, hemophilic arthritis, hepatitis,
   hiatal hernia, hyperplastic inflammation, hypertrophic arthritis,
   hypertrophic inflammation, infectional arthritis,
   infectious hepatitis, inflammation, irritable bowel syndrome,
   laryngitis, lumbago, lumbar rheumatism, mastoiditis, megacolon,
   meningitis, menopausal arthritis, metastatic inflammation,
   metritis, milk leg, mucous colitis, mumps meningitis, myelitis,
   necrotic inflammation, nephritis, neuritis,
   obliterative inflammation, ophthalitis, ophthalmia, orchitis,
   osseous rheumatism, osteitis, osteoarthritis, osteomyelitis,
   otitis, ovaritis, paradental pyorrhea, penitis, peptic ulcer,
   pericarditis, periodontitis, peritonitis, pharyngitis, phlebitis,
   podagra, polyp, proliferative arthritis, prostatitis, pyonephritis,
   pyorrhea, pyorrhea alveolaris, reactive inflammation, rheumatism,
   rheumatiz, rheumatoid arthritis, rhinitis, sclerosing inflammation,
   seroplastic inflammation, serous inflammation, serum hepatitis,
   simple inflammation, sinusitis, spastic colon,
   specific inflammation, stomach ulcer, subacute rheumatism,
   suppurative arthritis, suppurative inflammation,
   syphilitic arthritis, tennis elbow, testitis, thrombophlebitis,
   tonsilitis, torticollis, toxic inflammation,
   traumatic inflammation, tuberculous arthritis,
   tuberculous rheumatism, ulcer, ulcerative colitis,
   uratic arthritis, ureteritis, urethral arthritis, urethritis,
   uteritis, vaginitis, vertebral arthritis, visceral rheumatism,
   vulvitis, wryneck