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:

energizing \en"er*gi`zing\, a.
   1. imparting or capable of imparting vitality and energy.
      [WordNet sense 1]

   Syn: bracing, brisk, fresh, refreshing, refreshful, tonic.
        [1913 Webster]

              Those nobler exercises of energizing love. --Bp.
                                                  Horsley.
        [1913 Webster]

   2. supplying motive force. [WordNet sense 2]

   Syn: energizing, energising, kinetic. [PJC]

WordNet (r) 3.0 (2006):

energizing
    adj 1: supplying motive force; "the complex civilization of
           which Rome was the kinetic center"- H.O.Taylor [syn:
           energizing, energising, kinetic]
    n 1: the activity of causing to have energy and be active [syn:
         energizing, activating, activation]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "energizing":
   activating, alluring, animating, animation, animative, bracing,
   brisk, challenging, cheering, cordial, crisp, crispy, encouraging,
   enlivening, enlivenment, exciting, exhilarating, exhilaration,
   exhilarative, fresh, galvanic, galvanizing, invigorating,
   invigoration, invigorative, inviting, life-giving, piquant,
   prompting, provocative, provoking, quickening, refreshful,
   refreshing, regaling, revitalization, revival, rousing, stimulant,
   stimulating, stimulation, stimulative, stirring, tonic, viable,
   vitalization, vitalizing, vivifying, zestful, zesty