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• monkey wrench
  monkey wrench

  noun

  a wrench having an adjustable jaw permitting it to grasp nuts or the like of different sizes.
• monkey-wrench
  monkey-wrench

  verb (used with object)

  to ruin (plans, a schedule, etc.) unavoidably or, sometimes, deliberately.

monkey wrench

¹ American  

noun

1. especially British, adjustable spanner.  a wrench having an adjustable jaw permitting it to grasp nuts or the like of different sizes.

2. something that interferes with functioning; obstacle.

   He threw a monkey wrench into our plans.

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monkey-wrench ² American  

[muhng-kee-rench] / ˈmʌŋ kiˌrɛntʃ /

verb (used with object)

1. to ruin (plans, a schedule, etc.) unavoidably or, sometimes, deliberately.

   The storm monkey-wrenched our plans for a picnic.

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verb (used without object)

1. to prevent, delay, or sabotage industrialization or development of wilderness areas, especially through vandalism.

monkey wrench British  

noun

1. a wrench with adjustable jaws

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Other Word Forms

• monkey-wrencher
  noun

Etymology

Origin of monkey wrench¹

First recorded in 1855–60

Origin of monkey-wrench²

First recorded in 1800–10

Example Sentences

See Examples For:

monkey wrench monkey-wrench

But now two men on the federal death row in Terre Haute, Indiana have thrown a monkey wrench into Biden’s decision.

From Salon ● Jan. 11, 2025

One potential monkey wrench for the dollar, however, may be lurking in Japan.

From Reuters ● Aug. 18, 2023

“The last thing that a booming economy needs is to throw a monkey wrench into a system that we have that is working marvelously well.”

From Seattle Times ● Jul. 12, 2023

“You’ve thrown a monkey wrench into your campaign.”

From Washington Post ● Oct. 8, 2022

A monkey wrench that would free Citra from having to glean or be gleaned by Rowan.

From "Scythe" by Neal Shusterman

If Venezuela or any other country launched a surprise attack on the United States, I wouldn’t want the courts to monkey-wrench our prompt response.

From Los Angeles Times ● Mar. 25, 2025

But the court has yet to decide other pending cases that could monkey-wrench the regulatory system.

From Slate ● May 30, 2024

They’re a frisky if harmless sort of monkey-wrench gang, taking their last rolls with life’s fuzzy dice.

From New York Times ● Sep. 6, 2021

She delivers a satisfying, dramatic climax that represents the comeuppance of 19th-century colonialism, as Naila and the half brothers monkey-wrench the tools of the oppressor.

From Washington Post ● Mar. 25, 2019

At the entrance to the East Wing, they handed Patty her pie and monkey-wrench, and retreated to their own neighborhood.

From Just Patty by Relyea, C. M. (Charles Mark)