Nouns

(n)lethargy, lassitude, sluggishnessa state of comatose torpor (as found in sleeping sickness)
(n)inanition, lassitude, lethargy, slacknessweakness characterized by a lack of vitality or energy
(n)languor, lethargy, sluggishness, phlegm, flatnessinactivity; showing an unusual lack of energy“the general appearance of sluggishness alarmed his friends”