The Collaborative International Dictionary of English v.0.48:

Macerate \Mac"er*ate\, v. t. [imp. & p. p. Macerated; p. pr. &
   vb. n. Macerating.] [L. maceratus, p. p. of macerare to
   make soft, weaken, enervate; cf. Gr. ? to knead.]
   1. To make lean; to cause to waste away. [Obs. or R.]
      --Harvey.
      [1913 Webster]

   2. To subdue the appetites of by poor and scanty diet; to
      mortify. --Baker.
      [1913 Webster]

   3. To soften by steeping in a liquid, with or without heat;
      to wear away or separate the parts of by steeping; as, to
      macerate animal or vegetable fiber.
      [1913 Webster]

WordNet (r) 3.0 (2006):

macerate
    v 1: separate into constituents by soaking
    2: become soft or separate and disintegrate as a result of
       excessive soaking; "the tissue macerated in the water"
    3: soften, usually by steeping in liquid, and cause to
       disintegrate as a result; "macerate peaches"; "the gizzards
       macerates the food in the digestive system"
    4: cause to grow thin or weak; "The treatment emaciated him"
       [syn: waste, emaciate, macerate]

Moby Thesaurus II by Grady Ward, 1.0:

73 Moby Thesaurus words for "macerate":
   Sanforize, agonize, attenuate, bathe, bloody, brew, chew, claw,
   consume, convulse, crucify, crush, douche, drench, drouk, dry up,
   emacerate, emaciate, excruciate, flush, harrow, imbrue, imbue,
   impale, impregnate, infiltrate, infuse, inject, kill by inches,
   lacerate, lancinate, lave, leach, lixiviate, martyr, martyrize,
   mash, masticate, parch, percolate, permeate, preshrink, pulp,
   pulpify, punish, rack, rinse, rip, saturate, savage, scarify, sear,
   seethe, shrink, shrivel, smash, soak, sodden, sop, souse, squash,
   steep, thin, torment, torture, wash, waste, waste away, waterlog,
   weazen, wither, wizen, wring