foolproof
Americanadjective
-
involving no risk or harm, even when tampered with.
-
never-failing.
a foolproof method.
adjective
-
proof against failure; infallible
a foolproof idea
-
(esp of machines) proof against human misuse, error, etc
Etymology
Origin of foolproof
Explanation
When something is bound to work out, you can call it foolproof. Your foolproof plan for having a great summer might involve spending lots of time at the beach. If your dog tends to wander and can also jump six feet in the air, a foolproof plan for keeping her in your yard might involve an eight foot fence. You can also use foolproof as a verb: "I'm going to foolproof the instructions for heating up your dinner, so that no one sets the stove on fire this time." Foolproof is an early twentieth century American English word that combines fool, or "silly person" and proof, "resistant."
Vocabulary lists containing foolproof
Game Changer
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Old Yeller
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The Bad Beginning
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Although no preparation is foolproof, there are steps you can take to reduce risks at home and on the road.
From Los Angeles Times ● Sep. 22, 2026
Now that “learn to code” doesn’t seem to be the foolproof career advice it once was, thanks to artificial intelligence, Ms. Singer argues that it’s time for a reckoning.
From The Wall Street Journal ● Sep. 21, 2026
However, he cautioned that no system was foolproof.
From BBC ● Aug. 25, 2026
A foolproof strategy for redeeming credit-card points on flights or hotels?
From MarketWatch ● Aug. 11, 2026
With obvious pleasure Rosy showed Francis her data, and for the first time he was able to see how foolproof was her assertion that the sugar- phosphate backbone was on the outside of the molecule.
From "Double Helix" by James D. Watson
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Get a wordDefinitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
