The Collaborative International Dictionary of English v.0.48:

Disable \Dis*a"ble\ (?; 277), v. t. [imp. & p. p. Disabled; p.
   pr. & vb. n. Disabling.]
   1. To render unable or incapable; to destroy the force,
      vigor, or power of action of; to deprive of competent
      physical or intellectual power; to incapacitate; to
      disqualify; to make incompetent or unfit for service; to
      impair.
      [1913 Webster]

            A Christian's life is a perpetual exercise, a
            wrestling and warfare, for which sensual pleasure
            disables him.                         --Jer. Taylor.
      [1913 Webster]

            And had performed it, if my known offense
            Had not disabled me.                  --Milton.
      [1913 Webster]

            I have disabled mine estate.          --Shak.
      [1913 Webster]

   2. (Law) To deprive of legal right or qualification; to
      render legally incapable.
      [1913 Webster]

            An attainder of the ancestor corrupts the blood, and
            disables his children to inherit.     --Blackstone.
      [1913 Webster]

   3. To deprive of that which gives value or estimation; to
      declare lacking in competency; to disparage; to
      undervalue. [Obs.] "He disabled my judgment." --Shak.

   Syn: To weaken; unfit; disqualify; incapacitate.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

disabling \disabling\ adj.
   1. causing or having caused disability; rendering disabled;
      as, disabling injury.

   Syn: crippling, incapacitating.
        [WordNet 1.5]

   2. depriving of legal right; rendering legally disqualified;
      as, certain disabling restrictions disqualified him for
      citizenship. enabling

   Syn: disqualifying.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

disabling
    adj 1: that cripples or disables or incapacitates; "a crippling
           injury" [syn: crippling, disabling, incapacitating]
    2: depriving of legal right; rendering legally disqualified;
       "certain disabling restrictions disqualified him for
       citizenship" [syn: disabling, disqualifying] [ant:
       enabling]