derail

American  

[dee-reyl] / diˈreɪl /

verb (used with object)

• derails,
  present (3rd person singular)
• derailed,
  past participle,  past
• derailing
  present participle

1. to cause (a train, streetcar, etc.) to run off the rails of a track.

2. 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.

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verb (used without object)

• derails,
  present (3rd person singular)
• derailed,
  past participle,  past
• derailing
  present participle

1. (of a train, streetcar, etc.) to run off the rails of a track.

2. to become derailed; go astray.

noun

1. a track device for derailing rolling stock in an emergency.

derail British  

/ dɪˈreɪl /

verb

1. to go or cause to go off the rails, as a train, tram, etc

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noun

1. Also called: derailer.  a device designed to make rolling stock or locomotives leave the rails to avoid a collision or accident

Other Word Forms

Derived Forms

• derailment
  noun

Inflected Forms

Participles

• derailing
  present
• derailed
  past

Conjugated Forms

Present

• derail
  simple
• derails
  simple
• have derailed
  perfect
• has derailed
  perfect
• am derailing
  progressive
• are derailing
  progressive
• is derailing
  progressive
• have been derailing
  perfect progressive
• has been derailing
  perfect progressive

Past

• derailed
  simple
• had derailed
  perfect
• was derailing
  progressive
• were derailing
  progressive
• had been derailing
  perfect progressive

Future

• will derail
  simple
• will have derailed
  perfect
• will be derailing
  progressive
• will have been derailing
  perfect progressive

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."

Example Sentences

See Examples For:

derail derails derailed derailing

Ultimately, he believes there's little chance the leaks will "derail the potential success of the game".

From BBC ● Aug. 21, 2026

Andrew Copson, chief executive of Humanists UK which is in favour of a change in the law, said he hopes MPs will "look past renewed attempts to derail this long-overdue change".

From BBC ● Aug. 14, 2026

Both developments threaten to derail a potential deal to reopen the strait, a key waterway through which one-fifth of the world’s oil is transported.

From The Wall Street Journal ● Aug. 10, 2026

“For seniors who require ongoing care, exceeding asset or income limits can delay coverage, force private pay, or derail carefully laid plans.”

From MarketWatch ● Aug. 6, 2026

Maybe all the things I’m feeling for Natasha are just excuses to make it derail.

From "The Sun Is Also a Star" by Nicola Yoon

“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

Dodgers pitcher Tyler Glasnow laments not having an opportunity to play in the postseason after another elbow injury derails his season.

From Los Angeles Times ● Sep. 21, 2024

My sudden shaking derails my mom’s questioning and sends her into doctor mode.

From "Everything, Everything" by Nicola Yoon

A defect was found on railway tracks in East Sussex at the site where a train derailed leaving 30 injured, a report says.

From BBC ● Aug. 19, 2026

When I wrote last year about this group of longtime friends whose reunion got derailed by indecision, text-chain confusion and hurt feelings, it struck a chord with readers.

From The Wall Street Journal ● Aug. 15, 2026

Work includes examining the accident site, the derailed train and railway infrastructure.

From BBC ● Aug. 14, 2026

They were strong confident guys who were too cool and funny to be derailed by a cruel comment or a size-related mishap.

From Los Angeles Times ● Aug. 12, 2026

Coach never asked me to keep his secret—how anger derailed his career.

From "Black Brother, Black Brother" by Jewell Parker Rhodes

“True financial independence means you reasonably control what allows you to live the life you want without external things derailing you,” Welborn said.

From MarketWatch ● Jul. 12, 2026

Asian equities rose and oil prices were relatively stable early Friday, as the U.S. raced to keep Israel’s war in Lebanon from jeopardizing the fragile cease-fire and derailing talks with Iran this weekend.

From The Wall Street Journal ● Apr. 10, 2026

Most geopolitical strategists don’t see the war derailing U.S.-China relations even though China has been the primary buyer of Iran’s oil and a major financial lifeline.

From Barron's ● Apr. 7, 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

This was the only way to keep Cynthia from disrupting and derailing the entire lesson.

From "Look Both Ways" by Jason Reynolds

Related Words

• block
• deter
• filibuster
• hamper
• hinder
• impede
• interfere
• stall
• stonewall
• thwart