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.

But it does make clear that AI isn’t magic, nor are those who are making and marketing it infallible.

From Los Angeles Times • Mar. 26, 2026

They are never infallible or immune to misjudgment.

From Slate • Feb. 16, 2026

For the cubicle set, he was Kafka with an American accent and an infallible comic touch.

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

When things are going well, as they generally are, it is an infallible mechanism.

From "The Lives of a Cell" by Lewis Thomas