The Collaborative International Dictionary of English v.0.48:

Plunder \Plun"der\, n.
   1. The act of plundering or pillaging; robbery. See Syn. of
      Pillage.
      [1913 Webster]

            Inroads and plunders of the Saracens. --Sir T.
                                                  North.
      [1913 Webster]

   2. That which is taken by open force from an enemy; pillage;
      spoil; booty; also, that which is taken by theft or fraud.
      "He shared in the plunder." --Cowper.
      [1913 Webster]

   3. Personal property and effects; baggage or luggage. [Slang,
      Southwestern U.S.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Plunder \Plun"der\, v. t. [imp. & p. p. Plundered; p. pr. &
   vb. n. Plundering.] [G. pl["u]ndern to plunder, plunder
   frippery, baggage.]
   1. To take the goods of by force, or without right; to
      pillage; to spoil; to sack; to strip; to rob; as, to
      plunder travelers.
      [1913 Webster]

            Nebuchadnezzar plunders the temple of God. --South.
      [1913 Webster]

   2. To take by pillage; to appropriate forcibly; as, the enemy
      plundered all the goods they found.
      [1913 Webster]

   Syn: To pillage; despoil; sack; rifle; strip; rob.
        [1913 Webster]

WordNet (r) 3.0 (2006):

plunder
    n 1: goods or money obtained illegally [syn: loot, booty,
         pillage, plunder, prize, swag, dirty money]
    v 1: take illegally; of intellectual property; "This writer
         plundered from famous authors" [syn: loot, plunder]
    2: plunder (a town) after capture; "the barbarians sacked Rome"
       [syn: sack, plunder]
    3: steal goods; take as spoils; "During the earthquake people
       looted the stores that were deserted by their owners" [syn:
       plunder, despoil, loot, reave, strip, rifle,
       ransack, pillage, foray]
    4: destroy and strip of its possession; "The soldiers raped the
       beautiful country" [syn: rape, spoil, despoil,
       violate, plunder]

Moby Thesaurus II by Grady Ward, 1.0:

88 Moby Thesaurus words for "plunder":
   banditry, blackmail, boodle, booty, brigandage, brigandism,
   capture, depredate, depredation, desolate, despoil, despoiling,
   despoilment, despoliation, devastate, direption, fleece, forage,
   foraging, foray, freeboot, freebooting, graft, gut, haul,
   hot goods, knock off, knock over, lay waste, loot, looting, maraud,
   marauding, perks, perquisite, pickings, pillage, pillaging, pirate,
   plundering, pork barrel, prey on, prize, public till,
   public trough, raid, raiding, ransack, ransacking, rape, rapine,
   ravage, ravagement, ravaging, raven, ravish, ravishment, razzia,
   reive, reiving, relieve, rifle, rifling, rob, robbery, sack,
   sacking, seize, spoil, spoiling, spoils, spoils of office,
   spoliate, spoliation, squeeze, stealings, stick up, stolen goods,
   strip, swag, sweep, take, things, till, traps, tricks, vandalism,
   vandalize



The Devil's Dictionary (1881-1906):

PLUNDER, v.  To take the property of another without observing the
decent and customary reticences of theft.  To effect a change of
ownership with the candid concomitance of a brass band.  To wrest the
wealth of A from B and leave C lamenting a vanishing opportunity.