Definitions

infallible

[in-fal-uh-buhl] / ɪnˈfæl ə bəl /

ADJECTIVE

unerring, dependable

Synonyms

STRONGEST

authoritative flawless foolproof unbeatable

WEAK

acceptable accurate agreeable apodictic certain correct effective effectual efficacious efficient exact faultless handy helpful impeccable incontrovertible inerrable inerrant omniscient perfect positive reliable satisfactory satisfying sure surefire true trustworthy undeceivable unfailing unimpeachable unquestionable useful

Antonyms

WEAK

erring fallible faulty imperfect

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

For a while after that, they seemed totally infallible, a giant blue behemoth blocking out the light.

From BBC • May 6, 2026

They are never infallible or immune to misjudgment.

From Slate • Feb. 16, 2026

Dimon also said Tuesday that he didn’t think the Fed was infallible and had made mistakes.

From The Wall Street Journal • Jan. 13, 2026

To be sure, the “lipstick index” was never infallible, or even very popular, as far as economic theories go.

From MarketWatch • Dec. 12, 2025

I’d never labored under the false notion that my mom was infallible.

From "We Are the Ants" by Shaun David Hutchinson

Vocabulary lists containing infallible

The Vocabulary.com Top 1000

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ASVAB Word Knowledge

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"The Odyssey" by Homer, Books 1–7

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