The Collaborative International Dictionary of English v.0.48:

Overlook \O`ver*look"\, v. t. [imp. & p. p. Overlooked; p. pr.
   & vb. n. Overlooking.]
   1. To look down upon from a place that is over or above; to
      look over or view from a higher position; to be situated
      above, so as to command a view of; as, to overlook a
      valley from a hill; a hotel room that overlooks the
      marketplace. "The pile o'erlooked the town." --Dryden.
      [1913 Webster +PJC]

            [Titan] with burning eye did hotly overlook them.
                                                  --Shak.
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   2. Hence: To supervise; to watch over; sometimes, to observe
      secretly; as, to overlook a gang of laborers; to overlook
      one who is writing a letter.
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   3. To inspect; to examine; to look over carefully or
      repeatedly. "Overlook this pedigree." --Shak.
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            The time and care that are required
            To overlook and file and polish well. --Roscommon.
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   4. To look upon with an evil eye; to bewitch by looking upon;
      to fascinate. [Obs. or Prov. Eng.] --Shak.
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            If you trouble me I will overlook you, and then your
            pigs will die.                        --C. Kingsley.
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   5. To look over and beyond (anything) without seeing it; to
      miss or omit in looking; to fail to notice; to fail to
      observe; as, to overlook a mistake in addition; to
      overlook a missing bolt.
      [1913 Webster +PJC]

   6. Hence: To refrain from bestowing notice or attention upon;
      to disregard or deliberately ignore; to pass over without
      censure or punishment; to excuse or pardon (a fault,
      error, or misdeed).
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            The times of ignorance therefore God overlooked.
                                                  --Acts xvii.
                                                  30 (Rev. Ver.
                                                  )
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            They overlook truth in the judgments they pass.
                                                  --Atterbury.
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            The pardoning and overlooking of faults. --Addison.
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WordNet (r) 3.0 (2006):

overlook
    n 1: a high place affording a good view
    v 1: look past, fail to notice
    2: be oriented in a certain direction; "The house looks out on a
       tennis court"; "The apartment overlooks the Hudson" [syn:
       look out on, look out over, overlook, look across]
    3: leave undone or leave out; "How could I miss that typo?";
       "The workers on the conveyor belt miss one out of ten" [syn:
       neglect, pretermit, omit, drop, miss, leave out,
       overlook, overleap] [ant: attend to, take to heart]
    4: look down on; "The villa dominates the town" [syn:
       dominate, command, overlook, overtop]
    5: watch over; "I am overlooking her work"