The Collaborative International Dictionary of English v.0.48:

Incapacitate \In`ca*pac"i*tate\, v. t. [imp. & p. p.
   Incapacitated; p. pr. & vb. n. Incapacitating.] [Pref.
   in- not + capacitate.]
   [1913 Webster]
   1. To deprive of capacity or natural power; to disable; to
      render incapable or unfit; to disqualify; as, his age
      incapacitated him for war.
      [1913 Webster]

   2. (Law) To deprive of legal or constitutional requisites, or
      of ability or competency for the performance of certain
      civil acts; to disqualify.
      [1913 Webster]

            It absolutely incapacitated them from holding rank,
            office, function, or property.        --Milman.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

incapacitating \incapacitating\ adj.
   causing disability.

   Syn: crippling, disabling.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

incapacitating
    adj 1: that cripples or disables or incapacitates; "a crippling
           injury" [syn: crippling, disabling, incapacitating]