The Collaborative International Dictionary of English v.0.48:

Live \Live\ (l[imac]v), a. [Abbreviated from alive. See Alive,
   Life.]
   1. Having life; alive; living; not dead.
      [1913 Webster]

            If one man's ox hurt another's, that he die; then
            they shall sell the live ox, and divide the money of
            it.                                   --Ex. xxi. 35.
      [1913 Webster]

   2. Being in a state of ignition; burning; having active
      properties; as, a live coal; live embers. " The live
      ether." --Thomson.
      [1913 Webster]

   3. Full of earnestness; active; wide awake; glowing; as, a
      live man, or orator.
      [1913 Webster]

   4. Vivid; bright. " The live carnation." --Thomson.
      [1913 Webster]

   5. (Engin.) Imparting power; having motion; as, the live
      spindle of a lathe; live steam.
      [1913 Webster]

   6. (Elec.) Connected to a voltage source; as, a live wire.
      [PJC]

   7. (Broadcasting) Being transmitted instantaneously, as
      events occur, in contrast to recorded.
      [PJC]

   8. (Sport) Still in active play; -- of a ball being used in a
      game; as, a live ball.
      [PJC]

   9. Pertaining to an entertainment event which was performed
      (and possibly recorded) in front of an audience;
      contrasted to performances recorded in a studio without an
      audience.
      [PJC]

   Live birth, the condition of being born in such a state
      that acts of life are manifested after the extrusion of
      the whole body. --Dunglison.

   Live box, a cell for holding living objects under
      microscopical examination. --P. H. Gosse.

   Live feathers, feathers which have been plucked from the
      living bird, and are therefore stronger and more elastic.


   Live gang. (Sawing) See under Gang.

   Live grass (Bot.), a grass of the genus Eragrostis.

   Live load (Engin.), a suddenly applied load; a varying
      load; a moving load; as a moving train of cars on a
      bridge, or wind pressure on a roof.

   Live oak (Bot.), a species of oak (Quercus virens),
      growing in the Southern States, of great durability, and
      highly esteemed for ship timber. In California the
      Quercus chrysolepis and some other species are also
      called live oaks.

   Live ring (Engin.), a circular train of rollers upon which
      a swing bridge, or turntable, rests, and which travels
      around a circular track when the bridge or table turns.

   Live steam, steam direct from the boiler, used for any
      purpose, in distinction from exhaust steam.

   Live stock, horses, cattle, and other domestic animals kept
      on a farm. whole body.

   live wire
      (a) (Elec.) a wire connected to a power source, having a
          voltage potential; -- used esp. of a power line with a
          high potential relative to ground, capable of harming
          a person who touches it.
      (b) (Fig.) a person who is unusually active, alert, or
          aggressive.
          [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

live wire
    n 1: an alert and energetic person [syn: eager beaver, busy
         bee, live wire, sharpie, sharpy]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "live wire":
   activist, ball of fire, beaver, big-time operator, bustler,
   busy bee, charge, doer, dynamo, eager beaver, electric charge,
   enthusiast, go-getter, human dynamo, hustler, man of action,
   man of deeds, militant, new broom, operator, peeler,
   political activist, powerhouse, rustler, self-starter,
   take-charge guy, unit quantity, wheeler-dealer, winner