derail
Americanverb (used with object)
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to cause (a train, streetcar, etc.) to run off the rails of a track.
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to cause to fail or become deflected from a purpose; reduce or delay the chances for success or development of.
Being drafted into the army derailed his career for two years.
verb (used without object)
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(of a train, streetcar, etc.) to run off the rails of a track.
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to become derailed; go astray.
noun
verb
noun
Other Word Forms
Derived Forms
Inflected Forms
Participles
Conjugated Forms
Present
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derailsimple
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derailssimple
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have derailedperfect
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has derailedperfect
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am derailingprogressive
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are derailingprogressive
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is derailingprogressive
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have been derailingperfect progressive
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has been derailingperfect progressive
Past
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derailedsimple
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had derailedperfect
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was derailingprogressive
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were derailingprogressive
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had been derailingperfect progressive
Future
Etymology
Origin of derail
First recorded in 1840–50; from French dérailler, equivalent to dé- negative prefix + -railler, verbal derivative of rail “bar, beam” (from English ); see origin at de- rail 1
Explanation
When a train or a subway derails, its wheels accidentally leave the tracks. Train cars that derail can cause the cars behind them to crash. Mistakes by engineers or flaws in the track can derail a train or trolley, sending it off the rails and sometimes injuring the passengers. You can also use the verb derail figuratively, to mean "hinder someone" or "divert a process from going in its intended direction." For example, terrorists might derail ongoing peace talks by blowing up a bus. The word comes from the French dérailler, "go off the rails."
Vocabulary lists containing derail
This Week in Words: October 1 - 6, 2017
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This Week in Words: December 16 - 22, 2017
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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:
World number one Sinner, who defeated Jan-Lennard Struff earlier on Tuesday, will be hoping to derail the Serb's efforts in a repeat of last year's semi-final.
From BBC ● Jul. 7, 2026
Fighting in Lebanon in recent days has threatened to derail the peace deal.
From Barron's ● Jun. 22, 2026
It’s all of that and a longshot undertaking, given the countless obstacles that can derail their dream.
From Los Angeles Times ● Jun. 20, 2026
Oil prices pared gains after Iran said it ended military operations against Israel, easing fears that the latest exchange of fire could derail regional efforts to end the war and reopen the Strait of Hormuz.
From The Wall Street Journal ● Jun. 8, 2026
Just be sure not to derail them in the middle of a train of thought.
From "The Sense of Style" by Steven Pinker
“Most people think of retirement risk in terms of market crashes,” said Jeff Judge, a certified financial planner in Forest Hill, Md. “Healthcare is the one that actually derails the most plans I’ve seen.”
From MarketWatch ● Jun. 15, 2026
Their closeness derails Rausch’s “three steps ahead” scheming.
From Salon ● Jan. 28, 2026
If the ongoing scientific debate "derails that effort to try and understand if they're bad for us, that's not helpful", he said.
From Barron's ● Jan. 27, 2026
He’s worried about a crisis—like what happened with the nuclear industry—that sparks drastic policy changes that derails development.
From The Wall Street Journal ● Oct. 18, 2025
I need to get her out of here before my family derails my life just as it’s getting started.
From "The Sun Is Also a Star" by Nicola Yoon
China could well mediate the reconciliation, advancing the process that was thought to have been derailed by Iran’s war on its neighbors.
From The Wall Street Journal ● Jun. 25, 2026
If a year of protests could halt Tesla’s momentum, there’s no reason SpaceX’s surge can’t also be derailed.
From Slate ● Jun. 15, 2026
Technically, it’s Year 3, but after a torn ACL derailed her as a rookie two summers ago, it’s practically like Year 2 for the former Stanford star.
From Los Angeles Times ● Jun. 12, 2026
The explosion has reportedly set back Blue Origin’s progress by at least six months, not to mention derailed satellite-deployment timelines across the entire industry.
From MarketWatch ● Jun. 10, 2026
That’s what derailed attempts to domesticate cheetahs, the swiftest of all land animals, despite our strong motivation to do so for thousands of years.
From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond
According to a Bloomberg report, Iran is mulling pausing shipping through the Strait of Hormuz to prevent derailing future negotiations with the U.S.
From MarketWatch ● Apr. 15, 2026
The Gunners boss was then asked how he can prevent this form rolling into the rest of the season and derailing their Champions League and Premier League campaigns.
From BBC ● Apr. 4, 2026
For now, he is focused on derailing the Nexstar-Tegna deal.
From Los Angeles Times ● Mar. 20, 2026
“Is this derailing the underlying fundamentals? We think the answer is no.”
From The Wall Street Journal ● Mar. 4, 2026
This was the only way to keep Cynthia from disrupting and derailing the entire lesson.
From "Look Both Ways" by Jason Reynolds
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.
