The Collaborative International Dictionary of English v.0.48:

Butcher \Butch"er\, v. t. [imp. & p. p. Butchered; p. pr. &
   vb. n. Butchering.]
   1. To kill or slaughter (animals) for food, or for market;
      as, to butcher hogs.
      [1913 Webster]

   2. To murder, or kill, especially in an unusually bloody or
      barbarous manner. --Macaulay.
      [1913 Webster]

            [Ithocles] was murdered, rather butchered. --Ford.
      [1913 Webster]

   3. to bungle badly; to botch; -- used also when an object is
      damaged (literally or figuratively) in an activity; as,
      the new choir butchered the hymn.

   Syn: mangle. [PJC] butcher-bird
        butcher bird

The Collaborative International Dictionary of English v.0.48:

Butcher \Butch"er\ (b[.u]ch"[~e]r), n. [OE. bochere, bochier,
   OF. bochier, F. boucher, orig., slaughterer of buck goats,
   fr. OF. boc, F. bouc, a buck goat; of German or Celtic
   origin. See Buck the animal.]
   1. One who slaughters animals, or dresses their flesh for
      market; one whose occupation it is to kill animals for
      food.
      [1913 Webster]

   2. A slaughterer; one who kills in large numbers, or with
      unusual cruelty; one who causes needless loss of life, as
      in battle. "Butcher of an innocent child." --Shak.
      [1913 Webster]

   Butcher's meat, such flesh of animals slaughtered for food
      as is sold for that purpose by butchers, as beef, mutton,
      lamb, and pork.
      [1913 Webster]

WordNet (r) 3.0 (2006):

butcher
    n 1: a retailer of meat [syn: butcher, meatman]
    2: a brutal indiscriminate murderer
    3: a person who slaughters or dresses meat for market [syn:
       butcher, slaughterer]
    4: someone who makes mistakes because of incompetence [syn:
       bungler, blunderer, fumbler, bumbler, stumbler,
       sad sack, botcher, butcher, fuckup]
    v 1: kill (animals) usually for food consumption; "They
         slaughtered their only goat to survive the winter" [syn:
         butcher, slaughter]

Moby Thesaurus II by Grady Ward, 1.0:

215 Moby Thesaurus words for "butcher":
   Cain, amputate, annihilate, annihilator, apache, assassin,
   assassinator, assault, attack, ax, baggage man, bakehead, baker,
   barbarize, batter, be all thumbs, bisect, bloodletter,
   bloodshedder, blunder, blunder away, blunder into, blunder on,
   blunder upon, boggle, bollix up, bookdealer, bookseller, botch,
   brakeman, brakie, bravo, brutalize, bumble, bungle, bungler,
   burker, burn, button man, cannibal, carry on, carve, chandler,
   chop, cleave, clothing merchant, commit a gaffe, commit carnage,
   commit genocide, commit mass murder, conductor, confectioner, cut,
   cut away, cut in two, cut off, cutthroat, decimate, depopulate,
   desperado, destroy, destroyer, dichotomize, disembowel, dismember,
   dispatcher, dissever, draper, drysalter, eradicator, excise,
   executioner, exterminate, exterminator, faux pas, fireman,
   fishmonger, fishwife, fissure, florist, flounder, footplate man,
   footwear merchant, foul up, fruiterer, fuck up, fumble, furnisher,
   furrier, garroter, gash, go on, gorilla, greengrocer, grocer,
   groceryman, guard, gun, gunman, gunsel, haberdasher, hack, halve,
   hammer, hardwareman, hatchet man, head-hunter, hew, hit man,
   homicidal maniac, homicide, incise, ironmonger, jeweler, jigsaw,
   kill, killer, lance, lay waste, lineman, liquidate,
   liquor merchant, loot, louse up, lumber, man-eater, man-killer,
   manslayer, mar, massacre, massacrer, matador, maul, mess up,
   miscue, muddle, muff, mug, murder, murder wholesale, murderer,
   newsdealer, pare, perfumer, pesticide, pillage, play havoc with,
   poison, poisoner, porter, poulterer, prune, rage, railroad man,
   railroader, ramp, rampage, rant, rape, rave, redcap, rend, riot,
   ripper, rive, roar, ruin, sack, saddler, savage, saw, scissor,
   screw up, sever, slash, slaughter, slaughterer, slay,
   slay en masse, slayer, slice, slip, slit, smoke agent, snip,
   sow chaos, split, spoil, stationer, stationmaster, stoker, storm,
   strangler, stumble, sunder, switchman, tear, tear around,
   terrorize, thug, tobacconist, torpedo, trainboy, trainman,
   trainmaster, trigger man, trip, vandalize, vintner, violate,
   whittle, wine merchant, wreck, yardman, yardmaster