Definition of fail–safe
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
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1946
First Known Use of fail–safe
1946
2
fail–safe
noun
Definition of fail–safe
: a device or measure that makes something fail-safe
1975
First Known Use of fail–safe
1975
FAIL–SAFE Defined for English Language Learners
fail-safe
play
adjective
Definition of fail–safe for English Language Learners
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: certain not to fail
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