The Collaborative International Dictionary of English v.0.48:

Helpless \Help"less\, a.
   1. Destitute of help or strength; unable to help or defend
      one's self; needing help; feeble; weak; as, a helpless
      infant.
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            How shall I then your helpless fame defend? --Pope.
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   2. Beyond help; irremediable.
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            Some helpless disagreement or dislike, either of
            mind or body.                         --Milton.
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   3. Bringing no help; unaiding. [Obs.]
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            Yet since the gods have been
            Helpless foreseers of my plagues.     --Chapman.
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   4. Unsupplied; destitute; -- with of. [R.]
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            Helpless of all that human wants require. --Dryden.
      -- Help"less*ly, adv. -- Help"less*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

helpless
    adj 1: lacking in or deprived of strength or power; "lying ill
           and helpless"; "helpless with laughter" [syn: helpless,
           incapacitated]
    2: unable to function; without help [syn: helpless, lost]
    3: unable to manage independently; "as helpless as a baby"