foolproof

adjective

fool·​proof ˈfül-ˌprüf How to pronounce foolproof (audio)
Synonyms of foolproofnext
: so simple, plain, or reliable as to leave no opportunity for error, misuse, or failure
a foolproof plan

Examples of foolproof in a Sentence

DNA fingerprinting gives police a virtually foolproof way to link a suspect to a crime scene.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
One foolproof way to do as the Germans do is to wear their brands. — Carolin Lehmann, Travel + Leisure, 23 Aug. 2026 For some, these new measures promise to weed out AI use in the classroom, whether by discouraging students from relying on LLMs or equipping professors with a foolproof method of identifying its use. — Christopher Rim, Forbes.com, 21 Aug. 2026 Luckily, there’s a foolproof way to stay dry while looking fly — cuffed jeans. — Alyssa Grabinski, PEOPLE, 20 Aug. 2026 But, as anyone who’s watched an icy soda turn watery on a summer day can probably gather, moving hard ice to warm climates wasn’t exactly foolproof. — Mack Degeurin, Popular Science, 19 Aug. 2026 See All Example Sentences for foolproof

Word History

First Known Use

1874, in the meaning defined above

Time Traveler
The first known use of foolproof was in 1874

Rhymes for foolproof

See All Rhymes for foolproof

Browse Nearby Words

foolometer
foolproof
foolscap
See all Nearby Words

Cite this Entry

“Foolproof.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/foolproof. Accessed 1 Sep. 2026.

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Kids Definition

foolproof

adjective
fool·​proof ˈfül-ˈprüf How to pronounce foolproof (audio)
: done, made, or planned so well that nothing can go wrong
foolproof directions

More from Merriam-Webster on foolproof

Thesaurus: All synonyms and antonyms for foolproof

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