powerless

from WordNet (r) 3.0 (2006)

powerless
    adj 1: lacking power [ant: {powerful}]

from The Collaborative International Dictionary of English v.0.48

Powerless \Pow"er*less\, a.
   Destitute of power, force, or energy; weak; impotent; not
   able to produce any effect. -- {Pow"er*less*ly}, adv. --
   {Pow"er*less*ness}, n.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

67 Moby Thesaurus words for "powerless":
      anemic, asthenic, bloodless, chicken, cowardly, crippled,
      debilitated, decrepit, disabled, drooping, droopy, dull, effete,
      etiolated, faint, faintish, featherweight, feeble, flabby, flaccid,
      floppy, forceless, gone, gutless, helpless, imbecile, impotent,
      inactive, incapable, incapacitated, incompetent, ineffective,
      ineffectual, inefficacious, inert, infirm, languid, languorous,
      lightweight, limber, limp, listless, lustless, marrowless,
      nerveless, no-account, of no account, passive, pithless, pooped,
      rubbery, sapless, sinewless, slack, soft, spineless, strengthless,
      supine, unable, unauthoritative, unfit, unhardened, unnerved,
      unstrung, weak, weakly, without any weight