noun
languor, faintness, weariness, tiredness, fatigue, heaviness, stupor, dullness, drowsiness, yawning, exhaustion, burnout, prostration, drooping, torpor, torpidity, lethargy, apathy, ennui, stupefaction, inappetence, phlegm, hebetude, supineness, inertia, fag*, the dumps*, spring fever*; see also indifference 1.
Antonyms action*, vivaciousness, sprightliness.