Weakness characterized by a lack of vitality or energy

• Exhaustion resulting from lack of food
• Lethargy

Wiktionary Word definitions in Wiktionary
n. 1 emptiness. 2 (context medicine English) A state of advanced lack of adequate nutrition, food or water, or a physiological inability to utilize them; starvation. 3 (context philosophy English) A spiritual emptiness or lack of purpose or will to live, ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
c.1400, from Old French inanition , from Latin inanitionem (nominative inanitio ) "emptiness," noun of action from past participle stem of inanire "to empty," from inanis "empty, void, worthless, useless," of uncertain origin.

WordNet Word definitions in WordNet
n. weakness characterized by a lack of vitality or energy [syn: lassitude , lethargy ] exhaustion resulting from lack of food

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Inanition \In`a*ni"tion\, n. [F. inanition, L. inanitio emptiness, fr. inanire to empty, fr. inanis empty. Cf. Inane .] The condition of being inane; emptiness; lack of fullness, as in the vessels of the body; hence, specifically, exhaustion from lack of ...