infallible

1 of 2

adjective

Synonyms 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

infallibility

2 of 2

noun

: the quality or state of being infallible

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

Adjective I never claimed to be infallible. There is no infallible remedy to these problems.
Recent Examples on the Web
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Adjective
But Radcliffe noted that her method for screening polls is not infallible. ABC News, 18 Aug. 2026 Roberts is careful to note artificially intelligent algorithms like the type deployed by Exiger are not infallible. Michael Ashley, Forbes.com, 12 Aug. 2026 These words are also coming from a former priest, a man the world is taught to believe is infallible simply because of his profession. Whitney Friedlander, Variety, 6 Aug. 2026 Bash, Tapper, CNN and many others treated Fauci as an infallible god. Ian Miller Outkick, FOXNews.com, 3 Aug. 2026 See All Example Sentences for infallible

Word History

Etymology

Adjective

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

Noun

Medieval Latin infallibilitas, from infallibilis infallible + Latin -itas -ity

First Known Use

Adjective

15th century, in the meaning defined at sense 1

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

Browse Nearby Words

Cite this Entry

“Infallible.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/infallible. Accessed 24 Aug. 2026.

Kids Definition

infallible

adjective
1
: not capable of being wrong : unerring
an infallible memory
2
: not likely to fail : sure
an infallible remedy

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