If you undergo something necessary or unpleasant, it happens to you. New recruits have been undergoing training in recent weeks He underwent an agonising 48-hour wait for the results of tests. if you undergo a change, an unpleasant experience etc, it happens to you or is done to you
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"
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