The Collaborative International Dictionary of English v.0.48:

Icterus \Ic"te*rus\, n. [NL. See Icteric, a.] (Med.)
   The jaundice.
   [1913 Webster]

WordNet (r) 3.0 (2006):

icterus
    n 1: yellowing of the skin and the whites of the eyes caused by
         an accumulation of bile pigment (bilirubin) in the blood;
         can be a symptom of gallstones or liver infection or anemia
         [syn: jaundice, icterus]
    2: type genus of the Icteridae [syn: Icterus, genus Icterus]

Moby Thesaurus II by Grady Ward, 1.0:

84 Moby Thesaurus words for "icterus":
   abscess, ague, anemia, ankylosis, anoxia, apnea, asphyxiation,
   asthma, ataxia, atrophy, backache, bleeding, blennorhea, cachexia,
   cachexy, chill, chills, cholangitis, cholecystitis, cirrhosis,
   colic, constipation, convulsion, coughing, cyanosis, diarrhea,
   dizziness, dropsy, dysentery, dyspepsia, dyspnea, edema,
   emaciation, fainting, fatigue, fever, fibrillation, flux, growth,
   hemorrhage, hepatitis, hepatoma, high blood pressure, hydrops,
   hypertension, hypotension, indigestion, infectious hepatitis,
   inflammation, insomnia, itching, jaundice, labored breathing,
   low blood pressure, lumbago, marasmus, nasal discharge, nausea,
   necrosis, pain, paralysis, pruritus, rash, rheum, sallowness,
   sclerosis, seizure, serum hepatitis, shock, skin eruption,
   sneezing, sore, spasm, tabes, tachycardia, tumor, upset stomach,
   vertigo, vomiting, wasting, xanthochroism, yellow complexion,
   yellow race, yellow skin