Source : Webster's Revised Unabridged Dictionary (1913)

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.]

   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.

            Certain to undergo like doom.         --Milton.

   3. To be the bearer of; to possess. [Obs.]

            Their virtues else, be they as pure as grace, As
            infinite as man may undergo.          --Shak.

   4. To undertake; to engage in; to hazard. [Obs.]

            I have moved already Some certain of the
            noblest-minded Romans To undergo with me an
            enterprise.                           --Shak.

   5. To be subject or amenable to; to underlie. [Obs.]

            Claudio undergoes my challenge.       --Shak.

Underwent \Un`der*went"\,
   imp. of {Undergo}.

Source : WordNet®

underwent
     See {undergo}

undergo
     v 1: of mental or physical states or experiences; "get an idea";
          "experience vertigo"; "get nauseous"; "undergo a strange
          sensation"; "The chemical undergoes a sudden change";
          "The fluid undergoes shear"; "receive injuries"; "have a
          feeling" [syn: {experience}, {receive}, {have}, {get}]
     2: go or live through; "We had many trials to go through"; "he
        saw action in Viet Nam" [syn: {experience}, {see}, {go
        through}]
     3: accept or undergo, often unwillingly; "We took a pay cut"
        [syn: {take}, {submit}]
     [also: {underwent}, {undergone}]