The Collaborative International Dictionary of English v.0.48:

Dereliction \Der`e*lic"tion\, n. [L. derelictio.]
   1. The act of leaving with an intention not to reclaim or
      resume; an utter forsaking abandonment.
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            Cession or dereliction, actual or tacit, of other
            powers.                               --Burke.
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   2. A neglect or omission as if by willful abandonment.
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            A total dereliction of military duties. --Sir W.
                                                  Scott.
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   3. The state of being left or abandoned.
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   4. (Law) A retiring of the sea, occasioning a change of
      high-water mark, whereby land is gained.
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WordNet (r) 3.0 (2006):

dereliction
    n 1: a tendency to be negligent and uncaring; "he inherited his
         delinquency from his father"; "his derelictions were not
         really intended as crimes"; "his adolescent protest
         consisted of willful neglect of all his responsibilities"
         [syn: delinquency, dereliction, willful neglect]
    2: willful negligence