say it: uhn-dur-GOH
undergo is a verb meaning "pass through". It carries one recorded sense.
pass through
“The chemical undergoes a sudden change”
“The fluid undergoes shear”
“undergo a strange sensation”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for undergo come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.