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]