fail-safe
Americanadjective
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Electronics. pertaining to or noting a mechanism built into a system, as in an early warning system or a nuclear reactor, for insuring safety should the system fail to operate properly.
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equipped with a secondary system that insures continued operation even if the primary system fails.
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(sometimes initial capital letter) of, relating to, or designating a system of coded military controls in which bombers dispatched to a prearranged point as part of a standard operating procedure cannot advance farther without direct orders from a designated authority and cannot have the nuclear warheads they carry armed until they have passed their prearranged point.
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guaranteed to work; totally reliable.
a fail-safe recipe for a cheese soufflé.
noun
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(sometimes initial capital letter) the point beyond which the bombers cannot go without specific instruction; the fail-safe point.
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something designed to work or function automatically to prevent breakdown of a mechanism, system, or the like.
verb (used with object)
adjective
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designed to return to a safe condition in the event of a failure or malfunction
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(of a nuclear weapon) capable of being deactivated in the event of a failure or accident
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unlikely to fail; foolproof
verb
Other Word Forms
Inflected Forms
Participles
Conjugated Forms
Present
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fail-safesimple
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fail-safessimple
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have fail-safedperfect
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has fail-safedperfect
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am fail-safingprogressive
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are fail-safingprogressive
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is fail-safingprogressive
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have been fail-safingperfect progressive
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has been fail-safingperfect progressive
Past
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fail-safedsimple
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had fail-safedperfect
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was fail-safingprogressive
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were fail-safingprogressive
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had been fail-safingperfect progressive
Future
Etymology
Origin of fail-safe
First recorded in 1945–50; apparently from verb phrase to fail safe(ly)
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:
As a key oil producer, Saudi Arabia is relied upon to surge output and stabilize markets during crises, but any physical degradation of its export capacity neuters this critical fail-safe.
From The Wall Street Journal ● Mar. 2, 2026
The boats had rejected their inputs and automatically idled as a fail-safe, making them “dead” in the water.
From The Wall Street Journal ● Nov. 27, 2025
Congress created the Insurrection Act as a fail-safe in response to armed mobs attacking their neighbors and organized militias seeking to overthrow elected officials.
From Los Angeles Times ● Oct. 16, 2025
The NFL’s fail-safe against the worst excesses of institutional money is ego.
From Slate ● Dec. 12, 2024
But Seabiscuit was a fail-safe moneymaker, drawing record crowds and wagering virtually everywhere he showed his face.
From "Seabiscuit: An American Legend" by Laura Hillenbrand
However, discussions of fall-backs and fail-safes have not been welcome in the Wales camp while the possibility of automatic qualification remains.
From BBC ● Nov. 20, 2023
The local election board reported a simpler story: A new worker had incorrectly trashed the ballots, and its fail-safes had quickly identified the problem.
From New York Times ● Sep. 30, 2020
The company typically uses two or even three separate components as fail-safes for crucial tasks to reduce the possibility of a disastrous failure.
From Seattle Times ● Mar. 26, 2019
Fortunately, though, the new generation of submarines are built with so many levels of redundancy and fail-safes, the chances of anything bad happening are remote.
From Scientific American ● Feb. 12, 2018
An inmate had escaped from the Rikers Island Visit Room that same summer, despite the many fail-safes.
From "Newjack: Guarding Sing Sing" by Ted Conover
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.
