The Collaborative International Dictionary of English v.0.48:

Take off \Take" off`\, v. i.
   1. to begin a leap from a surface or a flight into the air;
      especially, (of a bird or an airplane) to leave the ground
      and begin to fly; as, flight CA123 took off on schedule at
      3:00 PM.
      [PJC]

   2. To begin a period of accelerating growth or development;
      as, the economy took off in the third quarter.
      [PJC]

   3. To begin a journey; to depart.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Take off \Take" off`\, v. t.
   1. To remove, as from the surface or outside; to remove from
      the top of anything; as, to take off a load; to take off
      one's hat, coat or other article of clothing; to take off
      a coat of paint from a surface.
      [1913 Webster +PJC]

   2. To cut off; as, to take off the head, or a limb.
      [1913 Webster]

   3. To destroy; as, to take off life.
      [1913 Webster]

   4. To remove; to invalidate; as, to take off the force of an
      argument.
      [1913 Webster]

   5. To withdraw; to call or draw away; as, the director took
      him off the project. --Locke.
      [1913 Webster + PJC]

   6. To swallow; as, to take off a glass of wine.
      [1913 Webster]

   7. To purchase; to take in trade. "The Spaniards having no
      commodities that we will take off." --Locke.
      [1913 Webster]

   8. To copy; to reproduce. "Take off all their models in
      wood." --Addison.
      [1913 Webster]

   9. To imitate; to mimic; to personate.
      [1913 Webster]

   10. To find place for; to dispose of; as, more scholars than
       preferments can take off. [R.] --Bacon.
       [1913 Webster]

   11. To discount or deduct (from a price); the dealer took off
       twenty percent on remaining toys.
       [PJC]

WordNet (r) 3.0 (2006):

take off
    v 1: leave; "The family took off for Florida" [syn: depart,
         part, start, start out, set forth, set off, set
         out, take off]
    2: take away or remove; "Take that weight off me!"
    3: depart from the ground; "The plane took off two hours late"
       [syn: take off, lift off]
    4: take time off from work; stop working temporarily [syn: take
       off, take time off]
    5: mimic or imitate in an amusing or satirical manner; "This
       song takes off from a famous aria"
    6: remove clothes; "take off your shirt--it's very hot in here"
    7: get started or set in motion, used figuratively; "the project
       took a long time to get off the ground" [syn: get off the
       ground, take off]
    8: prove fatal; "The disease took off"
    9: make a subtraction; "subtract this amount from my paycheck"
       [syn: subtract, deduct, take off] [ant: add, add
       together]

Moby Thesaurus II by Grady Ward, 1.0:

265 Moby Thesaurus words for "take off":
   abate, abscind, absquatulate, act, act a part, act as, act out,
   advance, allow, ameliorate, amend, amputate, annihilate, ape,
   aspire, ban, bar, bate, bear, become airborne, begin, begone,
   bereave of life, blast away, blast off, bob, burlesque, carry away,
   carry off, cast off, charge off, chloroform, claw skyward, clear,
   clear out, clip, come along, come on, commence, copy, copycat,
   crop, cull, cut, cut away, cut down, cut off, cut out, cut short,
   decamp, deduct, depreciate, deprive of life, destroy, detach,
   develop, discount, disengage, dispatch, dispose of, dive in, do,
   do away with, do for, do to death, dock, doff, dog it, douse, down,
   draw back, drop, eliminate, enact, end, enucleate, eradicate,
   except, excise, exclude, execute, exterminate, extinguish,
   extirpate, fall to, finish, finish off, float, fly, fly aloft,
   free, gain, gain altitude, gain ground, get ahead, get along,
   get rid of, get to, go ahead, go forward, graduate, grow better,
   hang, head, head into, hightail, hit off, hit off on, hover,
   imitate, immolate, impersonate, improve, isolate, jump off,
   kick back, kick off, kill, kite, knock off, lam,
   launch into eternity, lay low, leave the ground, liberate,
   light out, liquidate, look up, loose, loosen, lop, lynch, make,
   make allowance, make away with, make headway, make off,
   make progress, make strides, martyr, martyrize, masquerade as,
   meliorate, mend, mime, mimic, mock, mutilate, nip, pantomime, pare,
   parody, parrot, pass for, peel, perform, perk up, personate,
   pick out, pick up, pitch in, plane, play, play a part, plunge into,
   poise, poison, pose as, powder, pretend to be, progress, prune,
   purge, put away, put down, put off, put paid to, put to death,
   put to sleep, rebate, reduce, refund, release, remove,
   remove from life, root out, rotate, rule out, sacrifice, scrag,
   scram, send off, set about, set apart, set aside, set in, set out,
   set sail, set to, shape up, shave, shear, show improvement,
   skedaddle, skip, skip out, skyrocket, slaughter, slay, slip out of,
   soar, spire, split, stamp out, start, start in, start off,
   start out, starve, step out of, strike, strike off, strip,
   strip off, subtract, take, take a powder, take a premium,
   take away, take life, take off on, take out, taxi, throw off, to,
   travesty, truncate, turn to, unbar, unbind, unbolt, unbuckle,
   unbutton, unchain, unclasp, undo, unfasten, unfetter, unglue,
   unlace, unlatch, unleash, unlock, unloose, unloosen, unstick,
   unstrap, untie, unwrap, vamoose, weigh anchor, wipe out, withdraw,
   write off, zoom