Search Result for "lassitude": 
Wordnet 3.0

NOUN (3)

1. a state of comatose torpor (as found in sleeping sickness);
[syn: lethargy, lassitude, sluggishness]

2. a feeling of lack of interest or energy;
[syn: languor, lassitude, listlessness]

3. weakness characterized by a lack of vitality or energy;
[syn: inanition, lassitude, lethargy, slackness]

The Collaborative International Dictionary of English v.0.48:

Lassitude \Las"si*tude\ (l[a^]s"s[i^]*t[=u]d), n. [L. lassitudo, fr. lassus faint, weary; akin to E. late: cf. F. lassitude. See Late.] A condition of the body, or mind, when its voluntary functions are performed with difficulty, and only by a strong exertion of the will; languor; debility; weariness. [1913 Webster] The corporeal instruments of action being strained to a high pitch . . . will soon feel a lassitude. --Barrow. [1913 Webster]
WordNet (r) 3.0 (2006):

lassitude n 1: a state of comatose torpor (as found in sleeping sickness) [syn: lethargy, lassitude, sluggishness] 2: a feeling of lack of interest or energy [syn: languor, lassitude, listlessness] 3: weakness characterized by a lack of vitality or energy [syn: inanition, lassitude, lethargy, slackness]
Moby Thesaurus II by Grady Ward, 1.0:

91 Moby Thesaurus words for "lassitude": acedia, adynamia, anemia, apathy, atony, blah feeling, bloodlessness, blues, boredom, brain fag, cachexia, cachexy, cowardice, debilitation, debility, depression, disinterest, disregard, doldrums, drowsiness, dullness, dumps, enervation, enfeeblement, ennui, etiolation, exhaustion, eyestrain, faintness, fatigue, feebleness, flabbiness, flaccidity, goneness, heart strain, heaviness, hebetude, heedlessness, impotence, inanimation, indifference, insouciance, jadedness, lackadaisicalness, languidness, languishment, languor, languorousness, lenitude, lentor, lethargy, lifelessness, listlessness, mental fatigue, mental strain, oscitancy, overstrain, overtiredness, passivity, phlegm, powerlessness, prostration, satedness, sleep, sleepiness, sloth, slothfulness, slowness, sluggishness, slumber, softness, somnolence, stance fatigue, strain, strengthlessness, stupefaction, stupor, supineness, tedium, tiredness, torpidity, torpidness, torpitude, torpor, unconcern, unmindfulness, weakliness, weakness, wearifulness, weariness, world-weariness