The Collaborative International Dictionary of English v.0.48:

Undergo \Un`der*go"\, v. t. [imp. Underwent; p. p. Undergone
   (?; 115); p. pr. & vb. n. Undergoing.] [AS. underg[=a]n.
   See Under, and Go.]
   1. To go or move below or under. [Obs.]
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   2. To be subjected to; to bear up against; to pass through;
      to endure; to suffer; to sustain; as, to undergo toil and
      fatigue; to undergo pain, grief, or anxiety; to undergothe
      operation of amputation; food in the stomach undergoes the
      process of digestion.
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            Certain to undergo like doom.         --Milton.
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   3. To be the bearer of; to possess. [Obs.]
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            Their virtues else, be they as pure as grace,
            As infinite as man may undergo.       --Shak.
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   4. To undertake; to engage in; to hazard. [Obs.]
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            I have moved already
            Some certain of the noblest-minded Romans
            To undergo with me an enterprise.     --Shak.
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   5. To be subject or amenable to; to underlie. [Obs.]
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            Claudio undergoes my challenge.       --Shak.
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WordNet (r) 3.0 (2006):

undergo
    v 1: pass through; "The chemical undergoes a sudden change";
         "The fluid undergoes shear"; "undergo a strange sensation"

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "undergo":
   abide, afford, be exposed to, be subjected to, bear, bow, defer,
   encounter, endure, experience, feel, go through, have, know,
   labor under, live through, meet, meet up with, meet with,
   pass through, pay, run up against, see, spare, spare the price,
   spend, stand, stand under, submit, submit to, suffer, support,
   sustain, taste, tolerate, weather, well afford, withstand, yield