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.
      [1913 Webster]

   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.
      [1913 Webster]

   3. To inspect; to examine; to look over carefully or
      repeatedly. "Overlook this pedigree." --Shak.
      [1913 Webster]

            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).
      [1913 Webster +PJC]

            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"

Moby Thesaurus II by Grady Ward, 1.0:

209 Moby Thesaurus words for "overlook":
   Texas tower, abide with, accept, allow, allow for, autopsy, be big,
   be blind to, be caught napping, be caught out, be content with,
   be easy with, be inattentive, be neglectful, be negligent,
   be unwary, beacon, bear, bear with, bedevil, belvedere, bestraddle,
   bestride, bewitch, blank, bleachers, blink at, boss, bridge, brook,
   canvass, chaperon, chasm, check, check out, check over,
   check up on, clear, command, condone, conning tower, connive at,
   countenance, cut, cut dead, default, demonize, diabolize, discount,
   dismiss, disregard, dominate, endure, examine, excuse, face,
   face upon, fail, forget, forgive, front on, gallery, gazebo,
   give an examination, give no heed, give the go-by, give upon,
   gloss over, go over, grandstand, grin and abide, have,
   hear nothing, hear of, hex, hoodoo, ignore, indulge, inspect, jinx,
   judge not, keep in order, lapse, lean over backwards, leave out,
   leave unavenged, let go, let go by, let it go, let pass, let ride,
   let slide, let slip, lighthouse, listen to reason, live with,
   look at, look down upon, look out upon, look over,
   look right through, look toward, lookout, loophole, lose sight of,
   lose track of, make allowances for, make light of, make little of,
   miss, monitor, neglect, nod, not attend, not care for,
   not get involved, not heed, not listen, not notice, not think,
   not write off, obey, observation post, observatory, observe,
   obsess, omit, outlook, outtop, overarch, overhaul, overpass,
   oversee, overshadow, oversight, overtop, pardon, pass by,
   pass over, pass under review, pass up, pay no attention,
   pay no mind, peanut gallery, peephole, peer at, permit, peruse,
   pharos, pocket the affront, pooh-pooh, pore over, possess,
   postmortem, preterition, put up with, quarterback,
   refuse to acknowledge, refuse to recognize, regard with indulgence,
   review, ride herd on, ringside, ringside seat, rise above,
   run over, scan, scrutinize, see both sides, see nothing,
   set an examination, shrug, shrug it off, sighthole, size, size up,
   skip, sleep, slight, stand for, stand over, stomach, study,
   submit to, suffer, superintend, supervise, surmount, survey,
   suspend judgment, take, take care of, take for granted,
   take stock of, take the measure, think little of, tolerate, top,
   top gallery, tower, tower above, tower over, view with indulgence,
   voodoo, watchtower, wink at, witch, write off, yield to