infallible

[in-fal-uh-buhl]

adjective

1. absolutely trustworthy or sure.

   an infallible rule.

2. unfailing in effectiveness or operation; certain.

   an infallible remedy.

3. not fallible; exempt from liability to error, as persons, their judgment, or pronouncements.

   an infallible principle.

4. Roman Catholic Church.,  immune from fallacy or liability to error in expounding matters of faith or morals by virtue of the promise made by Christ to the Church.

noun

1. an infallible person or thing.

infallible

/ ɪnˈfæləbəl /

adjective

1. not fallible; not liable to error

2. not liable to failure; certain; sure

   an infallible cure

3. completely dependable or trustworthy

noun

1. a person or thing that is incapable of error or failure

Other Word Forms

• infallibility noun
• infallibleness noun
• infallibly adverb
• noninfallible adjective
• noninfallibly adverb

Word History and Origins

Origin of infallible¹

First recorded in 1375–1425; late Middle English word from Medieval Latin word infallibilis. See in- ³, fallible

Synonym Study

See reliable.

Example Sentences

The Alliance Defending Freedom, a right-wing Christian organization that purports to “affirm the inspired, infallible, inerrant, and authoritative Word of God,” has lent several of its attorneys to represent Chiles in the case.

From Salon

His view of himself, at least in public settings, is that of an infallible, almost deific, figure.

From Salon

And never be afraid to change the sequence and tendencies of that infallible trio of pitches, using instinct and feel to amplify his physical talent.

From Los Angeles Times

Rather than present Kim Jong Un as an infallible god as was the case for his father and grandfather, they elevated the loyal worker, he said.

From BBC

There's nuance and interpretation on many things, but there are certain infallible things you've just got to believe.

From Salon

Related Words

• authoritative 
• flawless 
• foolproof 
• unbeatable