lethargy

(noun) a state of comatose torpor (as found in sleeping sickness). Synonyms: lassitude, sluggishness.

(noun) weakness characterized by a lack of vitality or energy. Synonyms: inanition, lassitude, slackness.

(noun) inactivity; showing an unusual lack of energy. Synonyms: languor, sluggishness, phlegm, flatness. Example: "The general appearance of sluggishness alarmed his friends."