The Collaborative International Dictionary of English v.0.48:

Energetic \En`er*get"ic\, Energetical \En`er*get"ic*al\, a. [Gr.
   ?, fr. ? to work, be active, fr. ? active. See Energy.]
   1. Having energy or energies; possessing a capacity for
      vigorous action or for exerting force; active. "A Being
      eternally energetic." --Grew.
      [1913 Webster]

   2. Exhibiting energy; operating with force, vigor, and
      effect; forcible; powerful; efficacious; as, energetic
      measures; energetic laws.

   Syn: Forcible; powerful; efficacious; potent; vigorous;
        effective; strenuous. -- En`er*get"ic*al*ly, adv. --
        En`er*get"ic*al*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

energetically
    adv 1: in an energetic manner

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "energetically":
   actively, all out, allegretto, allegro, animatedly, ardently,
   assiduously, breezily, briskly, busily, cogently, con brio,
   diligently, dynamically, effectively, effectually, fervently,
   firmly, forcefully, forcibly, full tilt, hardly, heartily,
   in full swing, indefatigably, industriously, intensely, keenly,
   laboriously, lively, lustily, might and main, mightily, potently,
   powerfully, productively, relentlessly, sedulously, spiritedly,
   sprightly, strenuously, strikingly, strongly, tellingly,
   tirelessly, to good account, to good purpose, unsparingly,
   vehemently, vigorously, vivaciously, with a vengeance, with pep,
   with telling effect, zealously, zestfully