Synonyms and related words :
acedia, apathy, boredom, brain fag, debilitation, debility, drowsiness, dullness, enervation, enfeeblement, ennui, eyestrain, faintness, fatigue, goneness, heart strain, heaviness, hebetude, inanimation, indifference, jadedness, lackadaisicalness, languidness, languishment, languor, languorousness, lassitude, lenitude, lentor, lethargy, lifelessness, listlessness, mental fatigue, mental strain, oscitancy, overstrain, overtiredness, passivity, phlegm, satedness, sloth, slothfulness, slowness, sluggishness, somnolence, stance fatigue, strain, stupefaction, stupor, supineness, tiredness, torpidity, torpidness, torpitude, torpor, weakness, wearifulness, weariness, world-weariness