underbelly
Americannoun
plural
underbellies-
the lower abdomen; posterior ventral area, as of an animal's body.
-
the lower surface of an object; underside.
the underbelly of an airplane.
-
a vulnerable area; weak point.
an attack on the soft underbelly of Europe.
-
a dark, seamy, often hidden area or side.
a police officer continually exposed to the underbelly of society.
noun
-
the part of an animal's belly nearest to the ground
-
a vulnerable or unprotected part, aspect, or region
Etymology
Origin of underbelly
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.
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.
“Fargo” found its humor in the juxtaposition between “Minnesota Nice” and the dark, criminal underbelly it explored.
From Los Angeles Times • Apr. 17, 2026
Maybe it was the underbelly of all of the bravado and power-seeking—some desire to counter all the validation with the humiliation of knowing that, deep down, he’s just a revolting little worm.
From Slate • Apr. 15, 2026
Where the first wave of bands that emerged from downtown were more traditionally rock and roll and melodic, No Wave was the louder, darker, discordant underbelly and the logical next step.
From Salon • Apr. 14, 2026
The clue is in the title - US crime noir writer Jordan Harper is back with his latest thriller as he returns to his regular hunting ground, the seedy underbelly of LA.
From BBC • Dec. 24, 2025
He was pale, his complexion like the underbelly of a fish, and he wore black-rimmed glasses.
From "Geeks: How Two Lost Boys Rode the Internet Out of Idaho" by Jon Katz
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
