The Collaborative International Dictionary of English v.0.48:

Atrophy \At"ro*phy\, v. i.
   To waste away; to dwindle.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Atrophy \At"ro*phy\, n. [L. atrophia, Gr. ?; 'a priv. + ? to
   nourish: cf. F. atrophie.]
   A wasting away from lack of nourishment; diminution in bulk
   or slow emaciation of the body or of any part. --Milton.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Atrophy \At"ro*phy\, v. t. [p. p. Atrophied.]
   To cause to waste away or become abortive; to starve or
   weaken.
   [1913 Webster]

WordNet (r) 3.0 (2006):

atrophy
    n 1: a decrease in size of an organ caused by disease or disuse
         [syn: atrophy, wasting, wasting away]
    2: any weakening or degeneration (especially through lack of
       use) [syn: atrophy, withering]
    v 1: undergo atrophy; "Muscles that are not used will atrophy"

Moby Thesaurus II by Grady Ward, 1.0:

179 Moby Thesaurus words for "atrophy":
   Sanforizing, abnormality, abscess, acute disease, affection,
   affliction, ague, ailment, allergic disease, allergy, anemia,
   ankylosis, anoxia, apnea, asphyxiation, asthma, ataxia,
   attenuation, backache, bacterial disease, birth defect, bleeding,
   blennorhea, blight, cachexia, cachexy, cardiovascular disease,
   chill, chills, chronic disease, circulatory disease, colic,
   complaint, complication, condition, congenital defect,
   constipation, consume, consume away, consumption, convulsion,
   coughing, cyanosis, decadence, declension, declination, decline,
   defect, deficiency disease, deformity, degeneracy, degeneration,
   degenerative disease, devolution, diarrhea, disability, disease,
   disorder, distemper, dizziness, downfall, downgrade, dribble away,
   dropsy, drying, drying up, dysentery, dyspepsia, dyspnea, edema,
   emaceration, emaciate, emaciation, endemic, endemic disease,
   endocrine disease, epidemic disease, fainting, fatigue, fever,
   fibrillation, flux, functional disease, fungus disease,
   gastrointestinal disease, genetic disease, growth, handicap,
   hemorrhage, hereditary disease, high blood pressure, hydrops,
   hypertension, hypotension, iatrogenic disease, icterus, illness,
   indigestion, indisposition, infectious disease, infirmity,
   inflammation, insomnia, itching, jaundice, labored breathing,
   low blood pressure, lumbago, malady, malaise, marasmus,
   marcescence, morbidity, morbus, muscular disease, nasal discharge,
   nausea, necrosis, neurological disease, nutritional disease,
   occupational disease, organic disease, pain, pandemic disease,
   paralysis, parching, pathological condition, pathology, pine away,
   plant disease, preshrinkage, protozoan disease, pruritus,
   psychosomatic disease, rash, respiratory disease, rheum, rockiness,
   run to seed, run to waste, sclerosis, searing, secondary disease,
   seediness, seizure, shock, shrinkage, shrinking, shriveling,
   sickishness, sickness, signs, skin eruption, sneezing, sore, spasm,
   symptomatology, symptomology, symptoms, syndrome, tabes,
   tachycardia, the pip, thinning, tumor, upset stomach,
   urogenital disease, vertigo, virus disease, vomiting, wastage,
   waste, waste away, wasting, wasting disease, wilting, wither away,
   withering, worm disease