Enfeebling

from WordNet (r) 3.0 (2006)

enfeebling
    adj 1: causing debilitation [syn: {debilitative}, {enervating},
           {enfeebling}, {weakening}]

from The Collaborative International Dictionary of English v.0.48

Enfeeble \En*fee"ble\, v. t. [imp. & p. p. {Enfeebled}; p. pr. &
   vb. n. {Enfeebling}.] [OF. enfeblir, enfeiblir; pref. en- (L.
   in) + feble, F. faible, feeble. See {Feeble}.]
   To make feeble; to deprive of strength; to reduce the
   strength or force of; to weaken; to debilitate.
   [1913 Webster]

         Enfeebled by scanty subsistence and excessive toil.
                                                  --Prescott.

   Syn: To weaken; debilitate; enervate.
        [1913 Webster]