The Collaborative International Dictionary of English v.0.48:

Gut \Gut\, n. [OE. gut, got, AS. gut, prob. orig., a channel,
   and akin to ge['o]tan to pour. See FOUND to cast.]
   [1913 Webster]
   1. A narrow passage of water; as, the Gut of Canso.
      [1913 Webster]

   2. An intenstine; a bowel; the whole alimentary canal; the
      enteron; (pl.) bowels; entrails.
      [1913 Webster]

   3. One of the prepared entrails of an animal, esp. of a
      sheep, used for various purposes. See Catgut.
      [1913 Webster]

   4. The sac of silk taken from a silkworm (when ready to spin
      its cocoon), for the purpose of drawing it out into a
      thread. This, when dry, is exceedingly strong, and is used
      as the snood of a fish line.
      [1913 Webster]

   Blind gut. See Caecum, n.
      (b) .
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gut \Gut\, v. t. [imp. & p. p. Gutted; p. pr. & vb. n.
   Gutting.]
   1. To take out the bowels from; to eviscerate.
      [1913 Webster]

   2. To plunder of contents; to destroy or remove the interior
      or contents of; as, a mob gutted the house.
      [1913 Webster]

            Tom Brown, of facetious memory, having gutted a
            proper
            name of its vowels, used it as freely as he pleased.
                                                  --Addison.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gut
    n 1: the part of the alimentary canal between the stomach and
         the anus [syn: intestine, bowel, gut]
    2: a narrow channel or strait
    3: a strong cord made from the intestines of sheep and used in
       surgery [syn: catgut, gut]
    v 1: empty completely; destroy the inside of; "Gut the building"
    2: remove the guts of; "gut the sheep"

Moby Thesaurus II by Grady Ward, 1.0:

241 Moby Thesaurus words for "gut":
   ab ovo, abdomen, abomasum, affectional, affective, arm, armlet,
   audacity, automatic, backbone, balls, basal, basic, bay,
   bay window, bayou, beerbelly, belly, belt, bight, boca, boldness,
   bottle, bowel, bowels, bravery, breadbasket, bring to ruin, casual,
   clean, clean out, condemn, confound, constituent, constitutive,
   consume, corporation, courage, cove, craw, creek, crop, damn,
   daring, dauntlessness, deal destruction, decimate, deep-seated,
   demonstrative, depredate, desolate, despoil, destroy,
   determination, devastate, devour, diaphragm, disembowel, dissolve,
   draw, dress, dynamism, elemental, elementary, embonpoint,
   emotiometabolic, emotiomotor, emotional, emotiovascular, emotive,
   empty, endurance, engorge, entrails, essential, estuary, euripus,
   eviscerate, feeling, first stomach, fjord, fleece, forage, foray,
   forcefulness, freeboot, frith, fundamental, gizzard, glandular,
   gobble, gobble up, grit, gulf, gullet, gumption, gut with fire,
   guts, gutsiness, harbor, havoc, heart, heartfelt,
   honeycomb stomach, ill-advised, ill-considered, ill-devised,
   inadvertent, incinerate, indeliberate, inlet, innards, insides,
   instinctive, instinctual, integrity, interior, internal, internals,
   intestinal fortitude, intestines, intimate, intuitive, involuntary,
   inwards, kishkes, kyle, lay in ruins, lay waste, loch, loot,
   manyplies, maraud, material, maw, mettle, midriff, mouth, moxie,
   narrow, narrow seas, narrows, natural harbor, nerve, of soul,
   of the essence, offal, omasum, original, overdemonstrative, paunch,
   pillage, pluck, plunder, pot, potbelly, potgut, prey on, primal,
   primary, primitive, psalterium, pusgut, radical, raid, ransack,
   ravage, raven, ravish, reach, reflex, reflexive, reive, rennet bag,
   resolution, reticulum, rifle, road, roads, roadstead, ruin,
   ruinate, rumen, sack, sand, second stomach, shipwreck, snap,
   soulful, sound, spare tire, spirit, spoil, spoliate, spontaneous,
   spunk, stamina, stomach, strait, straits, strip, stuffing,
   substantial, substantive, swagbelly, swallow up, sweep,
   third stomach, throw into disorder, tripes, tum-tum, tummy,
   unadvised, uncalculated, unconscious, unconsidered, undeliberate,
   undeliberated, underbelly, underlying, undesigned, unintended,
   unintentional, unleash destruction, unleash the hurricane,
   unmeditated, unpremeditated, unstudied, unwilled, upheave,
   vandalize, vaporize, venter, ventripotence, viscera, visceral,
   vitals, waste, wrack, wreak havoc, wreck