The Collaborative International Dictionary of English v.0.48:

Restless \Rest"less\, a. [AS. restle['a]s.]
   1. Never resting; unquiet; uneasy; continually moving; as, a
      restless child. --Chaucer. "Restless revolution day by
      day." --Milton.
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   2. Not satisfied to be at rest or in peace; averse to repose
      or quiet; eager for change; discontented; as, restless
      schemers; restless ambition; restless subjects. "Restless
      at home, and ever prone to range." --Dryden.
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   3. Deprived of rest or sleep.
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            Restless he passed the remnants of the night.
                                                  --Dryden.
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   4. Passed in unquietness; as, the patient has had a restless
      night.
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   5. Not affording rest; as, a restless chair. --Cowper.
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   Restless thrush. (Zool.) See Grinder, 3.
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   Syn: Unquiet; uneasy; disturbed; disquieted; sleepless;
        agitated; unsettled; roving; wandering.
        [1913 Webster] -- Rest"less*ly, adv.-
        Rest"less*ness, n.
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WordNet (r) 3.0 (2006):

restlessly
    adv 1: in a restless manner; "he cracked his knuckles
           restlessly"