[1] : The Collaborative International Dictionary of English v.0.48

lethargy \leth"argy\ -jy^, n.; pl. -gies -ji^z. f.
   l'ethargie, l. lethargia, gr. lhqargi`a, fr. lh`qargos
   forgetful, fr. lh`qh forgetfulness. see lethe.
   1. morbid drowsiness; continued or profound sleep, from which
      a person can scarcely be awaked.
      1913 webster

   2. a state of inaction or indifference.
      1913 webster

            europe lay then under a deep lethargy. --atterbury.
      1913 webster
see also:
-gies lethe 

[2] : The Collaborative International Dictionary of English v.0.48

lethargy \leth"argy\, v. t.
   to lethargize. obs. --shak.
   1913 webster

[3] : WordNet (r) 2.0

lethargy
     n 1: a state of comatose torpor as found in sleeping sickness
          syn: lassitude, sluggishness
     2: weakness characterized by a lack of vitality or energy syn:
         inanition, lassitude
     3: inactivity; showing an unusual lack of energy syn: languor,
         sluggishness, phlegm
see also:
lassitude sluggishness inanition languor phlegm 

[4] : Moby Thesaurus II by Grady Ward, 1.0

176 moby thesaurus words for "lethargy":
   abstraction, abulia, acedia, alienation, aloofness, anxiety,
   anxiety equivalent, anxiety state, apathy, asininity, ataraxia,
   ataraxy, benumbedness, blah, blahs, blockishness, boobishness,
   boorishness, boredom, bovinity, catalepsy, catatonic stupor,
   cloddishness, coma, comatoseness, compulsion, crassness, crudeness,
   dejection, denseness, density, depression, detachment,
   dim-wittedness, dimness, disinterest, dispassion, disregard,
   dolce far niente, doltishness, doziness, drowsiness,
   dull-wittedness, dullardism, dullness, dumbness, duncery, elation,
   emotionalism, encephalitis lethargica, enervation, ennui, euphoria,
   exhaustion, fatigue, folie du doute, grossness, heartlessness,
   heaviness, hebetude, heedlessness, high, hopelessness,
   hypochondria, hysteria, hysterics, idleness, impassivity,
   inactivity, inanimation, inanition, inappetence, indifference,
   indolence, inertia, inertness, insensibility, insouciance,
   jadedness, lack of appetite, lackadaisicalness, languidness,
   languishment, languor, languorousness, lassitude, laziness,
   lenitude, lentor, lethargicalness, lifelessness, listlessness,
   loutishness, lumpishness, mania, melancholia, mental distress,
   narcohypnosis, narcolepsy, narcoma, narcosis, narcotic stupor,
   narcotization, ninnyism, nod, nonchalance, numbness, oafdom,
   oafishness, obsession, obtuseness, opacity, oscitancy, oscitation,
   pandiculation, passiveness, passivity, pathological indecisiveness,
   phlegm, phlegmaticalness, phlegmaticness, plucklessness,
   preoccupation, psychalgia, psychomotor disturbance, resignation,
   resignedness, satedness, sedation, shock, simpletonianism, sleep,
   sleepiness, sleeping sickness, sloth, slothfulness, slowness,
   sluggishness, slumber, somnolence, somnolency, sopor,
   soporifousness, sottishness, spiritlessness, spunklessness,
   stolidity, stretching, stupefaction, stupidity, stupor, supineness,
   swoon, thanatosis, thick-headedness, thick-wittedness, tic,
   tiredness, torpidity, torpidness, torpitude, torpor, trance,
   twitching, unconcern, unmindfulness, unresponsiveness,
   unteachability, weakness, weariness, withdrawal, withdrawnness,
   world-weariness, wrongheadedness, yawning, yokelism

Lethargy >> L Words
Lethargy, definition of term: Lethargy
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