The Collaborative International Dictionary of English v.0.48:

Knock \Knock\, n.
   1. A blow; a stroke with something hard or heavy; a jar.
      [1913 Webster]

   2. A stroke, as on a door for admittance; a rap. " A knock at
      the door." --Longfellow.
      [1913 Webster]

            A loud cry or some great knock.       --Holland.
      [1913 Webster]

   Knock off, See knock off in the vocabulary.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

knock off \knock off\, n.
   a device in a knitting machine to remove loops from the
   needles.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

knock off \knock off\, v. i. & t.
   1. to quit (working).
      [PJC]

   2. to accomplish; -- frequently used when the task is
      accomplished rapidly.
      [PJC]

   3. to kill; to defeat (opponents). [Colloq.]
      [PJC]

   4. to discount, to deduct (a sum from a price).
      [PJC]

   5. to rob.

   Syn: knock over.
        [PJC]

   6. to make a knockoff of; to copy or imitate, usually without
      permission or admission of copying. --[MW10]
      [PJC]

WordNet (r) 3.0 (2006):

knock off
    v 1: get rid of (someone who may be a threat) by killing; "The
         mafia liquidated the informer"; "the double agent was
         neutralized" [syn: neutralize, neutralise, liquidate,
         waste, knock off, do in]
    2: cut the price of [syn: shave, knock off]
    3: take by theft; "Someone snitched my wallet!" [syn: hook,
       snitch, thieve, cop, knock off, glom]
    4: write quickly; "She dashed off a note to her husband saying
       she would not be home for supper"; "He scratched off a thank-
       you note to the hostess" [syn: dash off, scratch off,
       knock off, toss off, fling off]
    5: stop pursuing or acting; "drop a lawsuit"; "knock it off!"
       [syn: drop, knock off]

Moby Thesaurus II by Grady Ward, 1.0:

198 Moby Thesaurus words for "knock off":
   abscind, accomplish, achieve, ad-lib, amputate, annihilate,
   assassinate, attain, author, ban, bar, bat out, bob, botch, break,
   breathe, bump off, bungle, buy it, call a strike, call it quits,
   cash in, cease, check in, check out, clip, close down, close shop,
   coauthor, collaborate, compass, compose, consummate, cook up, cool,
   croak, crop, cull, cut, cut away, cut off, cut out, dash off,
   deal with, desist, discharge, discontinue, discount, dispatch,
   dispose of, do, do anyhow, do by halves, do carelessly, do in,
   do offhand, do the job, do the trick, dock, draw back, drop off,
   dust off, editorialize, effect, effectuate, eliminate, enact,
   enucleate, eradicate, except, excise, exclude, execute,
   extemporize, extinguish, extirpate, fake, fake up, fetch, finish,
   formulate, free-lance, fudge up, fulfill, ghost, ghostwrite,
   give over, go on strike, go west, halt, have it, improvisate,
   improvise, indite, isolate, jury-rig, kick in, kick off,
   kick the bucket, knock out, knock over, knock together, lash up,
   lay off, leave off, liquidate, loot, lop, make, make up, manage,
   mutilate, nip, novelize, pamphleteer, pare, pass out, patch,
   patch together, patch up, pause, peel, peg out, perform, pick out,
   pipe off, play by ear, plunder, polish off, pop off, pound out,
   prepare, produce, prune, put away, quit, ransack, realize, recess,
   relieve, rifle, rob, root out, rough out, roughcast, roughhew,
   rule out, scenarize, scrap the plan, secure, set apart, set aside,
   shave, shear, shove off, shut down, shut up shop, slap up,
   stamp out, step off, stick up, stop for breath, strike, strike off,
   strip, strip off, subtract, succeed, surcease, take, take a break,
   take a recess, take a rest, take away, take care of, take five,
   take off, take out, take ten, take time out, throw off,
   throw on paper, throw together, toss off, toss out, toss together,
   trifle with, truncate, turn the trick, vamp, walk out, whip up,
   whomp up, wing it, wipe out, work, work out, write