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

Not without risk But even integration into the B-52 won’t be foolproof. — Christopher McFadden, Interesting Engineering, 11 Oct. 2026

There’s no foolproof security system to ensure that those who buzz in with a badge are necessarily the badge holders. — Laurent Belsie, Christian Science Monitor, 7 Oct. 2026

Scoring more than two goals per period is a pretty foolproof way to win hockey games. — Corey Masisak, Denver Post, 4 Oct. 2026

Potted plants are a foolproof way to introduce color and personality to your home exterior. — Sophie Flaxman, Better Homes & Gardens, 24 Sep. 2026

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