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

Briceno says gel pencils are also a foolproof way to introduce color. — Marci Robin, Allure, 24 July 2026

So mathematicians try to come up with foolproof methods for differentiating them. — Joseph Howlett, Scientific American, 23 July 2026

Read on for five foolproof ideas for what shoes to wear with satin pants, all inspired by street-style looks and ready to upgrade your early-fall rotation. — India Roby, Glamour, 16 July 2026

Cooking fruits and vegetables is the only foolproof way to kill the parasite, de Latour said. — Melina Khan, USA Today, 16 July 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