The Collaborative International Dictionary of English v.0.48:

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 food, either from partial or complete
   starvation, or from a disorder of the digestive apparatus,
   producing the same result.
   [1913 Webster]

         Feeble from inanition, inert from weariness. --Landor.
   [1913 Webster]

         Repletion and inanition may both do harm in two
         contrary extremes.                       --Burton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

inanition
    n 1: weakness characterized by a lack of vitality or energy
         [syn: inanition, lassitude, lethargy, slackness]
    2: exhaustion resulting from lack of food