fool·proof | \ˈfül-ˌprüf \

Definition of foolproof 

: 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

More: White House: Eagles at fault for cancellation, 'abandon their fans' This feel-good tradition of title teams paying house calls to the People’s House is damn near foolproof. Erik Brady, USA TODAY, "Trump has it wrong: Eagles disrespect their president, not their country," 5 June 2018 Ouija boards aren't foolproof and, yes, people often — whether consciously or unconsciously — move the planchette. Aliza Kelly Faragher, Allure, "A Beginner’s Guide to Communicating With Spirits on the Other Side," 19 June 2018 And despite advances in technology, radar is not foolproof and subject to human error, the National Motorists Association says. Michaelle Bond,, "In Pa., local cops can't use radar to catch speeders. That could soon change," 18 June 2018 These are obvious and foolproof. Do not neglect them. The Editors Of Gq, GQ, "How to Cure a Hangover: A Drinker’s Guide to Surviving the Morning After," 29 June 2018 But the locks aren’t foolproof and might even offer talented programmers an inviting challenge. Joshua Fruhlinger, WSJ, "Is It Smart to Install a Smart Lock?," 11 July 2018 But those administrative records are hardly foolproof, meaning the quality of the information may not be as good as getting it from the source. Jeffrey Mervis, Science | AAAS, "More money, more worries: 2020 census plans continue to generate controversy," 15 May 2018 Consumer Reports tested clothes treated with the insecticide permethrin and found that none of them was foolproof, plus the EPA classifies permethrin as a likely human carcinogen. Michael Roizen, M.d., And Mehmet Oz, Houston Chronicle, "An ounce of prevention is worth a pound of treatment," 24 June 2018 The Centers for Disease Control and Prevention has a list of preventive measures to avoid a tick bite but nothing is foolproof. Cathy Cassata, Fox News, "This family learned tick bites can transmit more than Lyme disease," 23 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'foolproof.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of foolproof

1902, in the meaning defined above

Keep scrolling for more

Learn More about foolproof

Statistics for foolproof

Last Updated

13 Oct 2018

Look-up Popularity

Time Traveler for foolproof

The first known use of foolproof was in 1902

See more words from the same year

Keep scrolling for more

More Definitions for foolproof



English Language Learners Definition of foolproof

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


fool·proof | \ˈfül-ˈprüf \

Kids Definition of foolproof

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

Keep scrolling for more

Comments on foolproof

What made you want to look up foolproof? Please tell us where you read or heard it (including the quote, if possible).


exaggeratedly or childishly emotional

Get Word of the Day daily email!

Test Your Vocabulary

Words from Greek and Roman Mythology Quiz

  • the-triumph-of-venus-by-alessandro-magnasco
  • Boreal comes from the name of the ancient Greek god of which wind?
Spell It

Can you spell these 10 commonly misspelled words?

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!