The Collaborative International Dictionary of English v.0.48:

de-energize \de-energize\ v. t.
   to deprive of energy, especially electrical energy; the door
   locks were de-energized and opened manually.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

de-energize
    v 1: deprive of energy [syn: de-energize, de-energise] [ant:
         arouse, brace, energise, energize, perk up,
         stimulate]