fail-safe

[ feyl-seyf ]

adjective

1. 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.
2. equipped with a secondary system that insures continued operation even if the primary system fails.
3. (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.
4. guaranteed to work; totally reliable:

   a fail-safe recipe for a cheese soufflé.

noun

1. (sometimes initial capital letter) the point beyond which the bombers cannot go without specific instruction; the fail-safe point.
2. something designed to work or function automatically to prevent breakdown of a mechanism, system, or the like.

verb (used with object)

, fail-safed, fail-saf·ing.

1. to make fail-safe.

fail-safe

adjective

1. designed to return to a safe condition in the event of a failure or malfunction
2. (of a nuclear weapon) capable of being deactivated in the event of a failure or accident
3. unlikely to fail; foolproof

verb

1. intr to return to a safe condition in the event of a failure or malfunction

Word History and Origins

Origin of fail-safe¹

First recorded in 1945–50; apparently from verb phrase to fail safe(ly)

Example Sentences

They had crossed paths once; Dad had wanted to turn Fail Safe into a movie, a project that Lumet eventually directed.

From The Daily Beast

So as we lurch toward the next “fail-safe” milestone, there must be a way out for both sides.

From The Daily Beast

For example, at Three Mile Island, a fail-safe feature actually made the meltdown worse.

From The Daily Beast

My Social Chef recommends the perfect, fail-safe roast chicken recipe.

From The Daily Beast

Internally, the communications beam to Thule Base had been interrupted; and the fail-safe had not failed-safely.

From Project Gutenberg

It designed ingenious models, devised foolproof laws, imposed fail-safe institutions and strongly "recommended" measures.

From Project Gutenberg