The Collaborative International Dictionary of English v.0.48:

Debilitation \De*bil`i*ta"tion\, n. [L. debilitatio: cf. F.
   d['e]bilitation.]
   The act or process of debilitating, or the condition of one
   who is debilitated; weakness.
   [1913 Webster]

WordNet (r) 3.0 (2006):

debilitation
    n 1: serious weakening and loss of energy [syn: debilitation,
         enervation, enfeeblement, exhaustion]