The Collaborative International Dictionary of English v.0.48:

Shrink \Shrink\, v. i. [imp. Shrankor Shrunkp. p. Shrunk
   or Shrunken, but the latter is now seldom used except as a
   participial adjective; p. pr. & vb. n. Shrinking.] [OE.
   shrinken, schrinken, AS. scrincan; akin to OD. schrincken,
   and probably to Sw. skrynka a wrinkle, skrynkla to wrinkle,
   to rumple, and E. shrimp, n. & v., scrimp. CF. Shrimp.]
   1. To wrinkle, bend, or curl; to shrivel; hence, to contract
      into a less extent or compass; to gather together; to
      become compacted.
      [1913 Webster]

            And on a broken reed he still did stay
            His feeble steps, which shrunk when hard thereon he
            lay.                                  --Spenser.
      [1913 Webster]

            I have not found that water, by mixture of ashes,
            will shrink or draw into less room.   --Bacon.
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            Against this fire do I shrink up.     --Shak.
      [1913 Webster]

            And shrink like parchment in consuming fire.
                                                  --Dryden.
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            All the boards did shrink.            --Coleridge.
      [1913 Webster]

   2. To withdraw or retire, as from danger; to decline action
      from fear; to recoil, as in fear, horror, or distress.
      [1913 Webster]

            What happier natures shrink at with affright,
            The hard inhabitant contends is right. --Pope.
      [1913 Webster]

            They assisted us against the Thebans when you shrank
            from the task.                        --Jowett
                                                  (Thucyd.)
      [1913 Webster]

   3. To express fear, horror, or pain by contracting the body,
      or part of it; to shudder; to quake. [R.] --Shak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Shrinking \Shrink"ing\,
   a. & n. from Shrink.
   [1913 Webster]

   Shrinking head (Founding), a body of molten metal connected
      with a mold for the purpose of supplying metal to
      compensate for the shrinkage of the casting; -- called
      also sinking head, and riser.
      [1913 Webster]

WordNet (r) 3.0 (2006):

shrinking
    n 1: process or result of becoming less or smaller; "the
         material lost 2 inches per yard in shrinkage" [syn:
         shrinking, shrinkage]
    2: the act of becoming less

Moby Thesaurus II by Grady Ward, 1.0:

126 Moby Thesaurus words for "shrinking":
   Olympian, Sanforizing, aloof, aseptic, atrophy, attenuation,
   backward, bashful, bashfulness, blank, boggle, boggling, chilled,
   chilly, cold, compunction, constrained, consumption, cool,
   cowardly, declining, demur, demurral, demurring, detached,
   diffidence, diffident, diminishing, discreet, distant, drying,
   drying up, dwindling, dying, ebbing, emaceration, emaciation,
   expressionless, fading, falter, faltering, fearful, fearing,
   fearsome, forbidding, frigid, frosty, goosy, guarded, hesitance,
   hesitancy, hesitant, hesitating, hesitation, icy, impassive,
   impersonal, in fear, inaccessible, introverted, jumpy, modest,
   modesty, mousy, nervous, objection, offish, parching, pause,
   preshrinkage, protest, qualm, qualm of conscience, qualmish,
   qualmishness, quiet, rabbity, receding, recoil, remote, removed,
   repressed, reserved, restrained, reticent, retiring, retreating,
   scary, scruple, scrupulosity, scrupulous, scrupulousness, searing,
   shaky, shivery, shrinkage, shriveling, shy, shyness, sinking,
   skittery, skittish, squeamish, standoff, standoffish, startlish,
   stickling, subdued, suppressed, thinning, timid, timorous,
   trembling, tremulous, trepidant, trigger-happy, unaffable,
   unapproachable, uncongenial, undemonstrative, unexpansive,
   ungenial, waning, wasting, withdrawn, withering