The Collaborative International Dictionary of English v.0.48:

Prey \Prey\, v. i. [imp. & p. p. Preyed; p. pr. & vb. n.
   Preying.] [OF. preier, preer, L. praedari, fr. praeda. See
   Prey, n.]
   To take booty; to gather spoil; to ravage; to take food by
   violence.
   [1913 Webster]

         More pity that the eagle should be mewed,
         While kites and buzzards prey at liberty. --Shak.
   [1913 Webster]

   To prey on or To prey upon.
   (a) To take prey from; to despoil; to pillage; to rob.
       --Shak.
   (b) To seize as prey; to take for food by violence; to seize
       and devour. --Shak.
   (c) To wear away gradually; to cause to waste or pine away;
       as, the trouble preyed upon his mind. --Addison.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Prey \Prey\, n. [OF. preie, F. proie, L. praeda, probably for
   praeheda. See Prehensile, and cf. Depredate,
   Predatory.]
   Anything, as goods, etc., taken or got by violence; anything
   taken by force from an enemy in war; spoil; booty; plunder.
   [1913 Webster]

         And they brought the captives, and the prey, and the
         spoil, unto Moses, and Eleazar the priest. --Num. xxxi.
                                                  12.
   [1913 Webster]

   2. That which is or may be seized by animals or birds to be
      devoured; hence, a person given up as a victim.
      [1913 Webster]

            The old lion perisheth for lack of prey. --Job iv.
                                                  ii.
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            Already sees herself the monster's prey. --Dryden.
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   3. The act of devouring other creatures; ravage.
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            Hog in sloth, fox in stealth, . . . lion in prey.
                                                  --Shak.
      [1913 Webster]

   Beast of prey, a carnivorous animal; one that feeds on the
      flesh of other animals.
      [1913 Webster]

WordNet (r) 3.0 (2006):

prey
    n 1: a person who is the aim of an attack (especially a victim
         of ridicule or exploitation) by some hostile person or
         influence; "he fell prey to muggers"; "everyone was fair
         game"; "the target of a manhunt" [syn: prey, quarry,
         target, fair game]
    2: animal hunted or caught for food [syn: prey, quarry]
    v 1: profit from in an exploitatory manner; "He feeds on her
         insecurity" [syn: prey, feed]
    2: prey on or hunt for; "These mammals predate certain eggs"
       [syn: raven, prey, predate]

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "prey":
   aim, bamboozle, beasts of venery, big game, bully, burden, butt,
   by-end, by-purpose, casualty, chase, cheat, consume, cozen,
   defraud, depress, destination, destroy, devour, distress, dupe,
   eat, end, end in view, exploit, fall guy, feed on, final cause,
   flimflam, game, go after, goal, gull, hoodwink, hunt, intimidate,
   kill, mark, martyr, mug, object, object in mind,
   object of compassion, objective, oppress, outfox, outsmart, outwit,
   poor devil, prey on, pursue, pursuit, pushover, quarry, quintain,
   reason for being, rook, seize, snooker, stalk, strain, sufferer,
   swindle, take advantage of, target, teleology, the hunted, trick,
   ultimate aim, underdog, use, venery, vex, victim, victimize,
   weigh on, weigh upon, worry, wretch