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Synonyms

underbelly

American  
[uhn-der-bel-ee] / ˈʌn dərˌbɛl i /

noun

  • underbellies
    plural
  1. the lower abdomen; posterior ventral area, as of an animal's body.

  2. the lower surface of an object; underside.

    the underbelly of an airplane.

  3. a vulnerable area; weak point.

    an attack on the soft underbelly of Europe.

  4. a dark, seamy, often hidden area or side.

    a police officer continually exposed to the underbelly of society.


underbelly British  
/ ˈʌndəˌbɛlɪ /

noun

  1. the part of an animal's belly nearest to the ground

  2. a vulnerable or unprotected part, aspect, or region

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Noun Inflected Forms

Etymology

Origin of underbelly

First recorded in 1600–10; under- + belly

Explanation

The underbelly of something is its secret weakness, something about it that's not protected from harm. Once a computer hacker discovers a network's underbelly, they're easily able to hack into it. Literally, an underbelly is just that: it's the abdomen of an animal, the soft lower belly. Often, that's also the most vulnerable part of an animal's body, since it contains major organs, and it's where the figurative meaning comes from. An alternate informal definition is "a hidden, criminal part of society," like the underbelly of a city where criminals trade stolen goods.

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

From what we've seen so far in the two gameplay trailers, the story will follow the pair in a Bonnie and Clyde-esque adventure through the seedy underbelly of America after an "easy score goes wrong".

From BBC Jun. 19, 2026

While the now-replaced aircraft sported a blue and white exterior, the new aircraft has a navy blue underbelly, thin red stripe and blue upper body.

From Barron's Jun. 19, 2026

“There’s a real underbelly of this vintage game with rag houses getting access to bulk product overseas and letting people sort through it,” he says.

From Los Angeles Times Jun. 3, 2026

It also exposed the AI boom’s underbelly: the grubby sidedeals, financial anxieties, short tempers and personal vendettas that have shaped modern technology every bit as much as the march toward machine consciousness.

From The Wall Street Journal May 16, 2026

Instead, we steered clear of the old residential neighborhoods bordering the Levee and headed deeper into the vice district’s underbelly.

From "The City Beautiful" by Aden Polydoros

Oseguera González’s counsel responded by telling jurors they should be skeptical of key witnesses “who have made that deal with the government” — an arrangement that he called “one of the underbellies of criminal justice.”

From Los Angeles Times Sep. 18, 2024

With creamy white underbellies and an unmistakable crown of shaggy feathers, a Philippine eagle makes a regal impression.

From National Geographic Jan. 28, 2021

The B-29s were flying so low that when he looked up, he could see the crimson flames from the ground reflected in the silvery metal underbellies of the aircraft.

From New York Times Mar. 9, 2020

But its high-profile status and historical willingness to turn a blind eye to the sources of its funding offers a vivid example of these deals’ underbellies.

From Washington Post Oct. 16, 2018

Thunder grumbled over the ocean and lightning lit the underbellies of the clouds, flashing from sea to sky and back again.

From "Ship Breaker" by Paolo Bacigalupi

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