undergo

From Middle English undergon, from Old English undergān (“to undergo, undermine, ruin”), equivalent to under- +‎ go. Cognate with Dutch ondergaan (“to undergo, perish, sink”), German untergehen (“to perish, sink, undergo”), Swedish undergå (“to undergo, go through”).

• (General American) IPA^(key): /ˌʌndɚˈɡoʊ/
• (Received Pronunciation) IPA^(key): /ˌʌndəˈɡəʊ/

• Audio (Southern England)

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• Rhymes: -əʊ
• Hyphenation: un‧der‧go

undergo (third-person singular simple present undergoes, present participle undergoing, simple past underwent, past participle undergone)

1. (transitive) To experience; to pass through a phase.

   Synonyms: go through, take, undercome

   The project is undergoing great changes.

   • 2013 January 1, Paul Bartel, Ashli Moore, “Avian Migration: The Ultimate Red-Eye Flight”, in American Scientist‎, volume 101, number 1, archived from the original on 5 March 2016, pages 47–48:

     Many of these classic methods are still used, with some modern improvements. For example, with the aid of special microphones and automated sound detection software, ornithologists recently reported […] that pine siskins (Spinus pinus) undergo an irregular, nomadic type of nocturnal migration.

2. (transitive) To suffer or endure; bear with.

   Synonyms: brook, put up with; see also Thesaurus:tolerate

   The victim underwent great trauma.

   She had to undergo surgery because of her broken leg.

3. (transitive, obsolete) To go or move under or beneath.

• undergang

• go under, grounde, guerdon, ungored