The Collaborative International Dictionary of English v.0.48:

Energize \En"er*gize\, v. i. [imp. & p. p. Energized; p. pr. &
   vb. n. Energizing.] [From Energy.]
   To use strength in action; to act or operate with force or
   vigor; to act in producing an effect.
   [1913 Webster]

         Of all men it is true that they feel and energize
         first, they reflect and judge afterwards. --J. C.
                                                  Shairp.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Energize \En"er*gize\, v. t.
   To give strength or force to; to make active; to alacrify;
   as, to energize the will.
   [1913 Webster]

WordNet (r) 3.0 (2006):

energize
    v 1: cause to be alert and energetic; "Coffee and tea stimulate
         me"; "This herbal infusion doesn't stimulate" [syn:
         stimulate, arouse, brace, energize, energise,
         perk up] [ant: calm, de-energise, de-energize,
         sedate, tranquilize, tranquillise, tranquillize]
    2: raise to a higher energy level; "excite the atoms" [syn:
       excite, energize, energise]

Moby Thesaurus II by Grady Ward, 1.0:

76 Moby Thesaurus words for "energize":
   activate, actuate, amplify, animate, arm, arouse,
   breathe life into, bring into being, bring into existence,
   bring to life, build up, call into being, call into existence,
   charge, compel, conceive, dynamize, egg on, electrify, empower,
   enable, endow with life, enliven, excite, exhilarate, fire, force,
   fortify, foster, galvanize, generate, give birth, give life to,
   hearten, impel, inflame, inspire, inspirit, invigorate, jazz up,
   kindle, liven, loop in, motivate, move, move to action, pep up,
   perk up, plug in, promote, propel, quicken, reinforce, rouse,
   set in motion, shock, short, short-circuit, snap up, spark,
   step down, step up, stiffen, stimulate, stir, sustain, switch off,
   switch on, turn off, turn on, urge, vitalize, vivify, waken, warm,
   zip up