in·​fal·​li·​ble | \ (ˌ)in-ˈfa-lə-bəl How to pronounce infallible (audio) \

Definition of infallible

1 : incapable of error : unerring an infallible memory
2 : not liable to mislead, deceive, or disappoint : certain an infallible remedy
3 : incapable of error in defining doctrines touching faith or morals

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Other Words from infallible

infallibility \ (ˌ)in-​ˌfa-​lə-​ˈbi-​lə-​tē How to pronounce infallibility (audio) \ noun
infallibly \ (ˌ)in-​ˈfa-​lə-​blē How to pronounce infallibly (audio) \ adverb

Synonyms & Antonyms for infallible


unerring, unfailing



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Did You Know?

Watch out when you hear about infallible predictions, an infallible plan, an infallible cure, or even infallible lip gloss. Infallible isn't a claim that scientists, engineers, and doctors like to make, so you're probably getting better information when the word not comes first. You may have heard the phrase "papal infallibility", which refers to the official position of the Roman Catholic church, adopted in the 19th century, that certain solemn statements made by a Pope about faith or morals were not to be questioned. Popes since then have been careful not to make many of these statements.

Examples of infallible in a Sentence

I never claimed to be infallible. There is no infallible remedy to these problems.

Recent Examples on the Web

Her infallible Dunaway-ness is on full display in Gucci’s new campaign for its polished, poised, and stylish bag, the Sylvie. Steff Yotka, Vogue, "Faye Dunaway Is a Style Icon, With a New Gucci Campaign to Prove It," 26 July 2018 His serve, which had been practically infallible through three rounds, was broken three times. Christopher Clarey,, "Roger Federer eliminated at Wimbledon," 11 July 2018 One problem, Ofri says, is a tendency in our society to view medical tests as infallible. Emily Sohn, Washington Post, "Even if a medical test shows an abnormality, you may not need to worry about it," 3 June 2018 Mexico: Mexico laid an egg in its final group stage match against Sweden, but round-of-16 opponent Brazil isn’t infallible. Staff,, "Weekend Read: A Case for All 16 Teams to Win the World Cup, Reflecting on Tyler Hilinski and More," 29 June 2018 Those opposing John Doe warrants and DNA exceptions point out that DNA evidence isn’t infallible. Ruth Padawer, New York Times, "Should Statutes of Limitations for Rape Be Abolished?," 19 June 2018 Roger Federer, while not infallible, can play when there is barbered grass underfoot. The Si Staff,, "Wimbledon 2018 Preview Roundtable: Predictions, Dark Horses, More," 29 June 2018 The person sitting across from you, unfortunately, is not infallible. Cari Romm, The Cut, "What to Do If Your Therapist Gives You Bad Advice," 25 June 2018 For spotless skin, Coqui Coqui’s all-natural mosquito repellent and Kiehl’s firming mask forge an infallible skin-soothing alliance. Jenna Rennert, Vogue, "What to Stock at Your Beach House, From SPF to a Luxurious Bug Repellant," 15 June 2018

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

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First Known Use of infallible

15th century, in the meaning defined at sense 1

History and Etymology for infallible

Middle English, from Medieval Latin infallibilis, from Latin in- + Late Latin fallibilis fallible

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Statistics for infallible

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Time Traveler for infallible

The first known use of infallible was in the 15th century

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More Definitions for infallible



English Language Learners Definition of infallible

: not capable of being wrong or making mistakes : not fallible
: certain to work properly or succeed


in·​fal·​li·​ble | \ in-ˈfa-lə-bəl How to pronounce infallible (audio) \

Kids Definition of infallible

1 : not capable of being wrong an infallible memory
2 : certain to succeed : sure an infallible remedy

Other Words from infallible

infallibly \ -​blē \ adverb

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Comments on infallible

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


to take the place or position of

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