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-wrench¹

First recorded in 1800–10

Example Sentences

The conservative justices threw a monkey wrench into the case with their opinion granting broad presidential immunity from prosecution, working through the implications of which will take at least another year.

From Los Angeles Times

But even in areas that typically don't face powerful storms, wildfires or floods, climate change is throwing intense monkey wrenches into what is expected.

From Salon

A monkey wrench in all this is the bipartisan Fiscal Responsibility Act of 2023, which became law in June to thwart the federal government defaulting on its debt.

From Scientific American

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

From Reuters

They could throw a monkey wrench into the federal effort to prosecute Trump for his most serious crimes before the 2024 election.

From Los Angeles Times