The Collaborative International Dictionary of English v.0.48:

Dropsy \Drop"sy\, n.; pl. Dropsies. [OE. dropsie, dropesie,
   OF. idropisie, F. hydropisie, L. hydropisis, fr. Gr. ?
   dropsy, fr. ? water. See Water, and cf. Hydropsy.] (Med.)
   An unnatural collection of serous fluid in any serous cavity
   of the body, or in the subcutaneous cellular tissue.
   --Dunglison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dropsy
    n 1: swelling from excessive accumulation of watery fluid in
         cells, tissues, or serous cavities [syn: edema, oedema,
         hydrops, dropsy]

Moby Thesaurus II by Grady Ward, 1.0:

105 Moby Thesaurus words for "dropsy":
   abscess, ague, anemia, ankylosis, anoxia, apnea, asphyxiation,
   asthma, ataxia, atrophy, backache, bleeding, blennorhea, bloat,
   bloatedness, bloating, blowing up, cachexia, cachexy, chill,
   chills, colic, constipation, convulsion, coughing, cyanosis,
   diarrhea, diastole, dilatation, dilation, distension, dizziness,
   dysentery, dyspepsia, dyspnea, edema, emaciation, fainting,
   fatigue, fever, fibrillation, flatulence, flatulency, flatus, flux,
   gassiness, growth, hemorrhage, high blood pressure, hydrops,
   hypertension, hypotension, icterus, indigestion, inflammation,
   inflation, insomnia, intumescence, itching, jaundice,
   labored breathing, low blood pressure, lumbago, marasmus,
   meteorism, nasal discharge, nausea, necrosis, pain, paralysis,
   pruritus, puff, puffiness, puffing, rash, rheum, sclerosis,
   seizure, shock, skin eruption, sneezing, sore, spasm, stretching,
   swell, swellage, swelling, swollenness, tabes, tachycardia,
   tumefaction, tumescence, tumidity, tumidness, tumor, turgescence,
   turgidity, turgidness, tympanism, tympany, upset stomach, vertigo,
   vomiting, wasting, windiness



Easton's 1897 Bible Dictionary:

Dropsy
   mentioned only in Luke 14:2. The man afflicted with it was cured
   by Christ on the Sabbath.