The Collaborative International Dictionary of English v.0.48:

Leprosy \Lep"ro*sy\ (l[e^]p"r[-o]*s[y^]), n. [See Leprous.]
   (Med.)
   A cutaneous disease which first appears as blebs or as
   reddish, shining, slightly prominent spots, with spreading
   edges. These are often followed by an eruption of dark or
   yellowish prominent nodules, frequently producing great
   deformity. In one variety of the disease, an[ae]sthesia of
   the skin is a prominent symptom. In addition there may be
   wasting of the muscles, falling out of the hair and nails,
   and distortion of the hands and feet with destruction of the
   bones and joints. It is incurable, and is probably
   contagious.
   [1913 Webster]

   Note: The disease now called leprosy, also designated as
         Lepra or Lepra Arabum, and Elephantiasis Gr[ae]corum,
         is not the same as the leprosy of the ancients. The
         latter was, indeed, a generic name for many varieties
         of skin disease (including our modern leprosy,
         psoriasis, etc.), some of which, among the Hebrews,
         rendered a person ceremonially unclean. A variety of
         leprosy of the Hebrews (probably identical with modern
         leprosy) was characterized by the presence of smooth,
         shining, depressed white patches or scales, the hair on
         which participated in the whiteness, while the skin and
         adjacent flesh became insensible. It was an incurable
         disease.
         [1913 Webster]

WordNet (r) 3.0 (2006):

leprosy
    n 1: chronic granulomatous communicable disease occurring in
         tropical and subtropical regions; characterized by inflamed
         nodules beneath the skin and wasting of body parts; caused
         by the bacillus Mycobacterium leprae [syn: leprosy,
         Hansen's disease]

Moby Thesaurus II by Grady Ward, 1.0:

153 Moby Thesaurus words for "leprosy":
   African lethargy, Asiatic cholera, Chagres fever, German measles,
   Haverhill fever, acne, acne vulgaris, acute articular rheumatism,
   ague, alkali disease, amebiasis, amebic dysentery, anthrax,
   bacillary dysentery, bastard measles, black death, black fever,
   blackwater fever, breakbone fever, brucellosis, bubonic plague,
   cachectic fever, cerebral rheumatism, chicken pox, cholera, cowpox,
   dandy fever, deer fly fever, dengue, dengue fever, dermamycosis,
   dermatitis, dermatosis, diphtheria, dumdum fever, dysentery,
   eczema, elephantiasis, encephalitis lethargica, enteric fever,
   epithelioma, erysipelas, erythema, exanthem, famine fever,
   five-day fever, flu, frambesia, glandular fever, grippe,
   hansenosis, heat rash, hepatitis, herpes, herpes simplex,
   herpes zoster, histoplasmosis, hives, hookworm, hydrophobia,
   impetigo, infantile paralysis, infectious mononucleosis,
   inflammatory rheumatism, influenza, itch, jail fever, jungle rot,
   kala azar, kissing disease, lepra, leptospirosis, lichen,
   lichen primus, loa loa, loaiasis, lockjaw, lupus, lupus vulgaris,
   madness, malaria, malarial fever, marsh fever, measles, meningitis,
   miliaria, milzbrand, mumps, ornithosis, osteomyelitis,
   paratyphoid fever, parotitis, parrot fever, pemphigus, pertussis,
   pneumonia, polio, poliomyelitis, polyarthritis rheumatism, ponos,
   prickly heat, pruigo, pruritus, psittacosis, psora, rabbit fever,
   rabies, rat-bite fever, relapsing fever, rheumatic fever,
   rickettsialpox, ringworm, rubella, rubeola, scabies, scarlatina,
   scarlet fever, schistosomiasis, septic sore throat, shingles,
   skin cancer, sleeping sickness, sleepy sickness, smallpox,
   snail fever, splenic fever, spotted fever, strep throat,
   swamp fever, tetanus, tetter, thrush, tinea, trench fever,
   trench mouth, tuberculosis, tularemia, typhoid, typhoid fever,
   typhus, typhus fever, undulant fever, vaccinia, varicella, variola,
   venereal disease, viral dysentery, whooping cough, yaws,
   yellow fever, yellow jack, zona, zoster



Easton's 1897 Bible Dictionary:

Leprosy
   (Heb. tsara'ath, a "smiting," a "stroke," because the disease
   was regarded as a direct providential infliction). This name is
   from the Greek lepra, by which the Greek physicians designated
   the disease from its scaliness. We have the description of the
   disease, as well as the regulations connected with it, in Lev.
   13; 14; Num. 12:10-15, etc. There were reckoned six different
   circumstances under which it might develop itself, (1) without
   any apparent cause (Lev. 13:2-8); (2) its reappearance (9-17);
   (3) from an inflammation (18-28); (4) on the head or chin
   (29-37); (5) in white polished spots (38, 39); (6) at the back
   or in the front of the head (40-44).

     Lepers were required to live outside the camp or city (Num.
   5:1-4; 12:10-15, etc.). This disease was regarded as an awful
   punishment from the Lord (2 Kings 5:7; 2 Chr. 26:20). (See
   MIRIAM; GEHAZI; UZZIAH.)

     This disease "begins with specks on the eyelids and on the
   palms, gradually spreading over the body, bleaching the hair
   white wherever they appear, crusting the affected parts with
   white scales, and causing terrible sores and swellings. From the
   skin the disease eats inward to the bones, rotting the whole
   body piecemeal." "In Christ's day no leper could live in a
   walled town, though he might in an open village. But wherever he
   was he was required to have his outer garment rent as a sign of
   deep grief, to go bareheaded, and to cover his beard with his
   mantle, as if in lamentation at his own virtual death. He had
   further to warn passers-by to keep away from him, by calling
   out, 'Unclean! unclean!' nor could he speak to any one, or
   receive or return a salutation, since in the East this involves
   an embrace."

     That the disease was not contagious is evident from the
   regulations regarding it (Lev. 13:12, 13, 36; 2 Kings 5:1).
   Leprosy was "the outward and visible sign of the innermost
   spiritual corruption; a meet emblem in its small beginnings, its
   gradual spread, its internal disfigurement, its dissolution
   little by little of the whole body, of that which corrupts,
   degrades, and defiles man's inner nature, and renders him unmeet
   to enter the presence of a pure and holy God" (Maclear's
   Handbook O.T). Our Lord cured lepers (Matt. 8:2, 3; Mark
   1:40-42). This divine power so manifested illustrates his
   gracious dealings with men in curing the leprosy of the soul,
   the fatal taint of sin.