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foolproof

[fool-proof] /ˈfulˌpruf/
adjective
1.
involving no risk or harm, even when tampered with.
2.
never-failing:
a foolproof method.
Origin of foolproof
1900-1905
An Americanism dating back to 1900-05; fool1 + -proof
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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Examples from the Web for foolproof
Contemporary Examples
Historical Examples
  • All of us—all the Academy top brass—develop a foolproof test for cadet maneuvers.

    Stand by for Mars! Carey Rockwell
  • He had to establish some sort of foolproof disguise, and he had to make contact with Earth's underground.

    The Status Civilization Robert Sheckley
  • There are a few sequences of words that really are foolproof, carrying their own atmosphere and dignity with them.

    The Book of Susan Lee Wilson Dodd
  • He had smashed the radio, a marvelously compact and foolproof outfit, arbitrarily tuned to a fixed short wave-length.

  • This time he wasn't afraid of meeting a Bandersnatch or anything else, for he had a method of escape that was foolproof.

    Insidekick Jesse Franklin Bone
British Dictionary definitions for foolproof

foolproof

/ˈfuːlˌpruːf/
adjective
1.
proof against failure; infallible: a foolproof idea
2.
(esp of machines) proof against human misuse, error, etc
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for foolproof
adj.

also fool-proof, 1902, American English, "safe against the incompetence of a fool," from fool (n.) + proof.

Online Etymology Dictionary, © 2010 Douglas Harper
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17
19
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