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

Juicy, zingy, and sweet, these peachy pork tenderloins are an easy and foolproof way to make a delicious dinner that will impress your guests. —Amanda Stanfield, Southern Living, 9 Jan. 2026

Natural Materials Introducing natural elements that bring the outdoors inside are a foolproof way to make your interior feel calming. —Kristin Hohenadel, The Spruce, 5 Jan. 2026

Olaplex The Full-On Shine Hair Routine Gift Set Soft, glossy hair never goes out of style, which makes Olaplex’s Full-On Shine Hair Routine Gift Set a foolproof pick. —Jennifer Hussein, Allure, 18 Dec. 2025

While the Registry is not entirely foolproof, cellphone owners may decide that any decrease in unsolicited phone calls is worth signing up. —Jeremy Tanner, The Hill, 12 Dec. 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