derail

American  

[dee-rayl] / 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

Heavy precipitation can also derail the soil compaction process, where crews lay down the soil in layers and go over each with a construction vehicle known as a roller.

From Los Angeles Times ● Oct. 8, 2026

The risk for Hyundai is that the needs of the moneymaking end of the business derail dreams of tomorrow.

From The Wall Street Journal ● Oct. 3, 2026

"You don't want to mess up," Sending says, adding that the wrong gift could potentially derail any larger objectives.

From BBC ● Sep. 25, 2026

While concerns over AI safety are not likely to derail Anthropic’s IPO plans, experts expect more regulation and safety disclosures.

From The Wall Street Journal ● Sep. 11, 2026

I practically see his mind spinning, his thoughts beginning to derail.

From "Internment" by Samira Ahmed

“I don’t see anything that derails economic or earnings growth,” said Amanda Agati, chief investment officer at PNC’s asset management group.

From Barron's ● Jul. 1, 2026

“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

The train of thought derails as soon as the server at Smoke House presents a large silver tray, its display slices of cakes layered and its pies adorned with ice cream.

From Los Angeles Times ● Oct. 31, 2025

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

From "Everything, Everything" by Nicola Yoon

England boycotted their fixture against Zimbabwe in Harare at the 2003 World Cup - a decision which ultimately derailed their campaign.

From BBC ● Oct. 1, 2026

Part of what derailed the bill was a dispute between the banking lobby and crypto companies over whether crypto platforms can offer interest-like rewards to stablecoin holders.

From The Wall Street Journal ● Sep. 28, 2026

Billy Bush, the veteran on-air host whose career was derailed by a crude off-camera conversation he had with President Trump in 2005, has signed on as a contributor to Fox News.

From Los Angeles Times ● Sep. 23, 2026

If some of these satellites get hacked, damaged, derailed, or destroyed, America’s ability to fight a war would be seriously degraded.

From Slate ● Sep. 17, 2026

From afar it brought to mind a bad train wreck, as if scores of ghostly white boxcars had derailed at the lip of the ice cap and tumbled down the slope willy-nilly.

From "Into the Wild" by Jon Krakauer

Yet her closeness to the 21-year-old Brahms, who rushed to her side and didn’t leave, risked derailing everything.

From The Wall Street Journal ● Sep. 25, 2026

“It sucks,” he said of the injury derailing him down the stretch.

From Los Angeles Times ● Sep. 23, 2026

Pezeshkian also warned Tuesday that a return by the United States to "a policy of pressure and threats" risked derailing diplomatic efforts to end the war.

From Barron's ● Sep. 1, 2026

“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

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