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

Other Words from infallible

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

Synonyms & Antonyms for infallible



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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 At-home tests are not infallible and are not a panacea for ending the pandemic. Stephen Collinson, CNN, 28 Dec. 2021 For a political party that presents itself as infallible, anything that suggests otherwise is perceived as dangerous. Michael Schuman, The Atlantic, 30 Nov. 2021 In the Middle Ages, kings ruled by divine right and were supposed to be infallible rulers. Paul Glover, Forbes, 10 Dec. 2021 The incident echoes the 2019 revelation that China had targeted thousands of iPhones in a similar manner—at the time, a wake-up call that iOS security isn't as infallible as it's perceived. Brian Barrett, Wired, 13 Nov. 2021 The exercise tested the limits of the eye test, strength of schedule comparisons, statistics and even what seemed like an infallible arbiter: head-to-head competition. New York Times, 2 Nov. 2021 For accurate and infallible books, get to know the basics of accounting before jumping to record any business transactions. Mike Kappel, Forbes, 9 Sep. 2021 Some can be harmful — especially when those in the highest-ranking positions manipulate other members for their own gain, and establish themselves as untouchable, infallible leaders who are owed obedience. Elizabeth Yuko, Rolling Stone, 18 Sep. 2021 Of course, last week’s Zero Day event provided a reminder that no company is infallible to the musings of the black hats. Daniel Newman, Forbes, 16 Sep. 2021

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

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Last Updated

11 Jan 2022

Cite this Entry

“Infallible.” Dictionary, Merriam-Webster, Accessed 18 Jan. 2022.

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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

More from Merriam-Webster on infallible

Nglish: Translation of infallible for Spanish Speakers

Britannica English: Translation of infallible for Arabic Speakers


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