fail
Americanverb (used without object)
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fails,
present (3rd person singular)
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failed,
past participle, past
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failing
present participle
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to fall short of success or achievement in something expected, attempted, desired, or approved.
The experiment failed because of poor planning.
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to receive less than the passing grade or mark in an examination, class, or course of study.
He failed in history.
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to be or become deficient or lacking; be insufficient or absent; fall short.
Our supplies failed.
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to dwindle, pass, or die away.
The flowers failed for lack of rain.
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to lose strength or vigor; become weak.
His health failed after the operation.
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to become unable to meet or pay debts or business obligations; become insolvent or bankrupt.
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(of a building member, structure, machine part, etc.) to break, bend, crush, or be otherwise destroyed or made useless because of an excessive load.
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to stop functioning or operating.
The electricity failed during the storm.
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Slang.
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to make an embarrassing or humorous mistake, be in a humiliating situation, etc., and be subject to ridicule.
Showed up late to the wedding? You fail!
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to be embarrassingly incompetent, stupid, etc..
She fails at life. I just failed at walking and fell on my face.
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to be bad or of inferior quality.
The play is terrible—even the music fails.
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verb (used with object)
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fails,
present (3rd person singular)
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failed,
past participle, past
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failing
present participle
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to be unsuccessful in the performance or completion of.
He failed to do his duty.
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(of some expected or usual resource) to prove of no use or help to.
His friends failed him. Words failed her.
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to receive less than a passing grade or mark in.
He failed history.
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to declare (a person) unsuccessful in a test, course of study, etc.; give less than a passing grade to.
The professor failed him in history.
noun
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Slang.
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an embarrassing or humorous mistake, humiliating situation, etc., that is subject to ridicule and given an exaggerated importance.
Their app update is a massive fail.
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the condition or quality resulting from having failed in this way.
His online post is full of fail.
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a person who fails in this way.
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Stock Exchange.
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a stockbroker's inability to deliver or receive security within the required time after sale or purchase.
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such an undelivered security.
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Obsolete. failure as to performance, occurrence, etc.
interjection
adjective
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unsuccessful; failed.
a totally fail policy.
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Slang.
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of or noting an embarrassing or humorous mistake, humiliating situation, etc..
the top 100 funniest fail photos on the internet.
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embarrassingly incompetent, stupid, etc.
Why am I so fail?
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very bad or of inferior quality.
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idioms
verb
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to be unsuccessful in an attempt (at something or to do something)
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(intr) to stop operating or working properly
the steering failed suddenly
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to judge or be judged as being below the officially accepted standard required for success in (a course, examination, etc)
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(tr) to prove disappointing, undependable, or useless to (someone)
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(tr) to neglect or be unable (to do something)
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(intr) to prove partly or completely insufficient in quantity, duration, or extent
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(intr) to weaken; fade away
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(intr) to go bankrupt or become insolvent
noun
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a failure to attain the required standard, as in an examination
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definitely; with certainty
noun
Other Word Forms
Derived Forms
Inflected Forms
Participles
Conjugated Forms
Present
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failsimple
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failssimple
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have failedperfect
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has failedperfect
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am failingprogressive
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are failingprogressive
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is failingprogressive
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have been failingperfect progressive
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has been failingperfect progressive
Past
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failedsimple
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had failedperfect
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was failingprogressive
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were failingprogressive
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had been failingperfect progressive
Future
Etymology
Origin of fail
First recorded in 1175–1225; Middle English failen, from Anglo-French, Old French faillir, from unattested Vulgar Latin fallīre, for Latin fallere “to disappoint, deceive”
Explanation
The verb fail describes something that stops working, like brakes in a car that fail, or is found to be unacceptable, like restaurants that fail their inspection for cleanliness. The verb fail comes from the Old French word faillir, meaning “be lacking,” “miss,” or “not succeed.” You can fail an exam, which means you didn't get at least a minimum number of points to pass. You can fail to live up to your potential, meaning you aren't able to meet expectations. When businesses fail, it means financial problems force them to close.
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:
If the engine were to fail, for example, a pilot can sometimes perform an “autorotation” procedure to use altitude and forward momentum to force the rotors to turn, easing their descent.
From Los Angeles Times ● Sep. 19, 2026
If you did, the current market would likely fail, and prices would be much lower.
From MarketWatch ● Sep. 18, 2026
In the 2024 special “The End of Obesity,” a doctor recommends semaglutide for Cartman after diet and exercise fail to meaningfully improve his health.
From Salon ● Sep. 18, 2026
Some researchers believe the committee's advice does not act as a barrier to Heathrow's expansion and will fail to achieve the reduction in planet-warming gases required.
From BBC ● Sep. 16, 2026
“Both Haldeman and Henry seem to have an idea—which I think is mistaken—that even if we fail in Vietnam we can still survive politically,” the president wrote in his diary.
From "Most Dangerous: Daniel Ellsberg and the Secret History of the Vietnam War" by Steve Sheinkin
When Sen. Alan Simpson quotes from “Othello” in defense of Thomas, he uses Shakespeare’s lyrical authority but fails to realize that he is in fact invoking the false words of the tragedy’s villain, Iago.
From Los Angeles Times ● Sep. 18, 2026
The big risk for investors in autocallables, though, is a major drawdown in the reference assets that fails to recover back above the maturity barrier in a severe and prolonged bear market.
From MarketWatch ● Sep. 18, 2026
Such deaths typically occur in the first trimester, after a pregnancy fails to properly implant in the uterus and begins to develop elsewhere, most commonly inside a fallopian tube.
From Salon ● Sep. 13, 2026
If SB Energy fails to start data-center operations by its deadline for PORTS-Pike, it must give OpenAI a free day of base rent for each day of delay.
From The Wall Street Journal ● Sep. 10, 2026
The reactor is surrounded by a containment structure, a chamber of steel-reinforced concrete as much as 5 feet thick—strong enough to hold the contents of the reactor if the steel vessel fails.
From "Meltdown" by Deirdre Langeland
Early Saturday morning, Armstrong said the final bill was an improvement on earlier drafts, even as he acknowledged that it failed.
From The Wall Street Journal ● Sep. 20, 2026
One reason the shares of so-called smid-cap energy stocks that insiders are buying look cheap is that they have failed to keep up with oil prices, Messier told me in a recent interview.
From MarketWatch ● Sep. 19, 2026
But while the family waited at Asmara International Airport on 11 December 2003, she failed to emerge through arrivals with the other passengers.
From BBC ● Sep. 19, 2026
The Chargers, who were favored by 9½ points, failed to generate anything close to a rhythm.
From Los Angeles Times ● Sep. 19, 2026
It meant “thank you”—that much Penelope knew, from her failed attempts to get the children to say it—but what could Svetlana be thanking her for?
From "The Long-Lost Home" by Maryrose Wood
Pharmacies are failing on AI diet pill checks, writes Sunday People.
From BBC ● Sep. 20, 2026
Dodgers owner Mark Walter and multiple insurance companies he owns are being sued for allegedly failing to disclose an ongoing federal probe to customers.
From Los Angeles Times ● Sep. 19, 2026
But it was panned by investors for failing to provide much new information, and the Cybercab is currently in a limited deployment in Austin.
From MarketWatch ● Sep. 17, 2026
To cover the shortfall, she worked 20 hours per week alongside her studies, a decision she says contributed to her failing her first-year exams.
From BBC ● Sep. 16, 2026
When I heard this, I was beginning to feel a strange chill and failing at the heart.
From "Jane Eyre" by Charlotte Brontë
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.
