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

An InStyle writer, 29, and her mom, 61, still reach for it for foolproof coverage that doesn’t budge. —Reece Andavolgyi, InStyle, 22 Jan. 2026

Forecasting is never foolproof, but since the pandemic, professional forecasters have been mostly on target, if a little pessimistic. —The Editorial Board, Chicago Tribune, 12 Jan. 2026

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

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