foolproof

adjective

fool·​proof ˈfül-ˌprüf 

: 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

His favorite camera at the time was the Nikon FM2, a manual film camera and generally foolproof piece of equipment that only used a battery for the exposure meter—so not much could go wrong. —Anna Cafolla, Vogue, 23 May 2025

Potted plants are a foolproof way to introduce color and personality to your home exterior. —Sophie Flaxman, Better Homes & Gardens, 11 June 2025

Yes, good old paper is the best and only way to have foolproof elections. —New York Daily News Editorial Board, New York Daily News, 29 May 2025

But maybe throwing your script into a pit of other scripts in the hopes of earning someone’s attention was never a foolproof strategy. —Harrison Richlin, IndieWire, 6 May 2025

Word History

First Known Use

1874, in the meaning defined above

Rhymes for foolproof

• aloof
• behoof
• disproof
• flameproof
• greaseproof
• leakproof
• reproof
• soundproof
• bulletproof
• fireproof
• waterproof
• weatherproof

Kids Definition

foolproof

adjective

fool·​proof ˈfül-ˈprüf 

: done, made, or planned so well that nothing can go wrong

foolproof directions