ADJECTIVE (2)

1. lacking power or ability;
- Example: "Technology without morality is barbarous morality without technology is impotent"- Freeman J.Dyson;
- Example: "felt impotent rage"

2. (of a male) unable to copulate;

The Collaborative International Dictionary of English v.0.48:

Impotent \Im"po*tent\, a. [F. impotent, L. impotens, -entis;
   pref. im- not + potens potent, powerful. See Potent.]
   1. Not potent; wanting power, strength. or vigor. whether
      physical, intellectual, or moral; deficient in capacity;
      destitute of force; weak; feeble; infirm.
      [1913 Webster]

            There sat a certain man at Lystra, impotent inhis
            feet.                                 --Acts xiv. 8.
      [1913 Webster]

            O most lame and impotent conclusion!  --Shak.
      [1913 Webster]

            Not slow to hear,
            Nor impotent to save.                 --Addison.
      [1913 Webster]

   2. Wanting the power of self-restraint; incontrolled;
      ungovernable; violent.
      [1913 Webster]

            Impotent of tongue, her silence broke. --Dryden.
      [1913 Webster]

   3. (Med.) Wanting the power of procreation; unable to
      copulate; also, sometimes, sterile; barren; specifically,
      in males: unable to achieve or sustain a penile erection.
      [1913 Webster +PJC]

The Collaborative International Dictionary of English v.0.48:

Impotent \Im"po*tent\, n.
   One who is impotent. [R.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

impotent
    adj 1: lacking power or ability; "Technology without morality is
           barbarous; morality without technology is impotent"-
           Freeman J.Dyson; "felt impotent rage" [ant: potent,
           stiff, strong]
    2: (of a male) unable to copulate [ant: potent, virile]

Moby Thesaurus II by Grady Ward, 1.0:

152 Moby Thesaurus words for "impotent":
   acarpous, aimless, anemic, arid, asexual, asthenic, barren,
   blank cartridge, bloodless, careless, castrated, castrato,
   celibate, chicken, childless, cold, cowardly, crippled,
   debilitated, desert, desolate, disabled, drained, dried-up,
   drooping, droopy, dry, dud, dull, easy, easygoing, effete,
   emasculate, emasculated, enervated, enfeebled, etiolated, eunuch,
   eunuchized, exhausted, faint, faintish, fallow, featherweight,
   feckless, feeble, flabby, flaccid, floppy, forceless, frail,
   frigid, fruitless, frustrated, gaunt, gelded, gelding, gone,
   gutless, helpless, imbecile, imprecise, inadequate, incompetent,
   indifferent, ineffective, ineffectual, inefficacious, inept,
   infecund, infertile, infirm, invalid, invertebrate, issueless,
   jejune, languid, languorous, lax, leached, lenient, lightweight,
   limber, limp, listless, loose, lustless, marrowless, meaningless,
   menopausal, negligent, nerveless, neuter, neutral, no go,
   no-account, nonfertile, nonproducing, nonproductive, nonprolific,
   of no account, of no use, overindulgent, overpermissive,
   permissive, pithless, pointless, pooped, powerless, purposeless,
   relaxed, remiss, rubbery, sapless, sexless, sine prole, sinewless,
   slack, slipshod, sloppy, soft, spineless, sterile, strengthless,
   sucked dry, superfluous, teemless, unauthoritative, unavailing,
   uncultivated, unfertile, unfruitful, unhardened, unnerved,
   unplowed, unproductive, unprolific, unrestrained, unsexed,
   unsexual, unsown, unstrung, untilled, useless, virgin, waste,
   wasted, weak, weakling, weakly, without any weight,
   without issue