foolproof

[ fool-proof ]
See synonyms for foolproof on Thesaurus.com
adjective
  1. involving no risk or harm, even when tampered with.

  2. never-failing: a foolproof method.

Origin of foolproof

1
An Americanism dating back to 1900–05; fool1 + -proof

Words Nearby foolproof

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use foolproof in a sentence

British Dictionary definitions for foolproof

foolproof

/ (ˈfuːlˌpruːf) /


adjective
  1. proof against failure; infallible: a foolproof idea

  2. (esp of machines) proof against human misuse, error, etc

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