The Collaborative International Dictionary of English v.0.48:

Forget \For*get"\, v. t. [imp. Forgot(Forgat, Obs.); p. p.
   Forgotten, Forgot; p. pr. & vb. n. Forgetting.] [OE.
   forgeten, foryeten, AS. forgietan, forgitan; pref. for- +
   gietan, gitan (only in comp.), to get; cf. D. vergeten, G.
   vergessen, Sw. f["o]rg[aum]ta, Dan. forgiette. See For-,
   and Get, v. t.]
   1. To lose the remembrance of; to let go from the memory; to
      cease to have in mind; not to think of; also, to lose the
      power of; to cease from doing.
      [1913 Webster]

            Bless the Lord, O my soul, and forget not all his
            benefits.                             --Ps. ciii. 2.
      [1913 Webster]

            Let my right hand forget her cunning. --Ps. cxxxvii.
                                                  5.
      [1913 Webster]

            Hath thy knee forget to bow?          --Shak.
      [1913 Webster]

   2. To treat with inattention or disregard; to slight; to
      neglect.
      [1913 Webster]

            Can a woman forget her sucking child? . . . Yes,
            they may forget, yet will I not forget thee. --Is.
                                                  xlix. 15.
      [1913 Webster]

   To forget one's self.
      (a) To become unmindful of one's own personality; to be
          lost in thought.
      (b) To be entirely unselfish.
      (c) To be guilty of what is unworthy of one; to lose one's
          dignity, temper, or self-control.
          [1913 Webster]

WordNet (r) 3.0 (2006):

forget
    v 1: dismiss from the mind; stop remembering; "I tried to bury
         these unpleasant memories" [syn: forget, bury] [ant:
         remember, think of]
    2: be unable to remember; "I'm drawing a blank"; "You are
       blocking the name of your first wife!" [syn: forget,
       block, blank out, draw a blank] [ant: call back,
       call up, recall, recollect, remember, retrieve,
       think]
    3: forget to do something; "Don't forget to call the chairman of
       the board to the meeting!" [ant: bear in mind, mind]
    4: leave behind unintentionally; "I forgot my umbrella in the
       restaurant"; "I left my keys inside the car and locked the
       doors" [syn: forget, leave]

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "forget":
   abandon, blink at, blow up, brush aside, brush off,
   bury the hatchet, charge off, charge to experience,
   consign to oblivion, discount, dismiss, disregard, draw a blank,
   drop the subject, fail, fluff, forget about it, forget it,
   forgive and forget, ignore, lay aside, leave behind, let it go,
   let it pass, let slip, lose, lose sight of, not remember, omit,
   overlook, overpass, push aside, put aside, set aside, shrug off,
   slight, sneeze at, think nothing of, thrust aside, turn away from,
   write off