adynamia

from WordNet (r) 3.0 (2006)

adynamia
    n 1: lack of strength or vigor (especially from illness)

from The Collaborative International Dictionary of English v.0.48

adynamia \ad`y*na"mi*a\ ([a^]d`[i^]*n[=a]"m[i^]*[.a]), n. [NL.
   adynamia, fr. Gr. 'adynami`a lack of strength; 'a priv +
   dy`namis power, strength.] (Med.)
   Considerable debility of the vital powers; asthenia.
   --Dunglison.
   [1913 Webster + AS]

   2. Specifically: (Med) Absence of motor power or force.
      [AS]