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Showing results for infallible.
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.

They are never infallible or immune to misjudgment.

From Slate • Feb. 16, 2026

They aren't infallible but they will increase the hassle factor for criminals.

From BBC • Feb. 7, 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

Why did a church with an infallible papal teacher need councils?

From The Wall Street Journal • Dec. 4, 2025

“It is this denial,” he announced, “that has plunged the prince deep into the melancholy of love. Fasting, brooding, sighing, and disordered dress are its most infallible signs.”

From "Ophelia" by Lisa Klein

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.