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]