fail-safe

1 of 2

adjective

ˈfāl-ˌsāf 

1

: incorporating some feature for automatically counteracting the effect of an anticipated possible source of failure

2

: being or relating to a safeguard that prevents continuing on a bombing mission according to a preconceived plan

3

: having no chance of failure : infallibly problem-free

… the little black dress … has consistently been the fail-safe solution for night.

—Vogue

fail-safe

2 of 2

noun

: a device or measure that makes something fail-safe

Synonyms of fail-safe

Adjective

• reliable
• surefire
• infallible

Noun

• precaution
• preventive

Examples of fail-safe in a Sentence

Adjective

flowers have been traditionally regarded as the fail-safe gift for Valentine's Day

Noun

there are so many fail-safes built into the system that a highly unlikely series of mistakes would have to be made before failure could occur

Recent Examples on the Web

Adjective

Consider this the fail-safe way to make a statement during the colder months—a leopard-print coat that's both fiercely cool and classic. —Andrea Cheng, InStyle, 29 Dec. 2025

Larry Anglisano, an aviation journalist for AVBrief, described Autoland as a fail-safe for when the airplane is in working order but the pilot might not be able to take control. —Sarah Horbacewicz, CBS News, 22 Dec. 2025

Noun

This is an opportunity for revenue generation that provides a fail-safe against property taxes. —Abigail Hasebroock, Sun Sentinel, 20 Jan. 2026

His fail-safe designs made Valentino the king of the red carpet, the go-to man for A-listers’ awards ceremony needs. —Jenny Barchfield, Los Angeles Times, 19 Jan. 2026

Word History

First Known Use

Adjective

1931, in the meaning defined at sense 1

Noun

1975, in the meaning defined above

Rhymes for fail-safe

• unsafe
• vouchsafe
• chafe
• safe
• waif