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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.

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

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

From BBC • Feb. 7, 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

He was seventy-two when he died, trim, strong, easygoing, seemingly infallible, and though he was my stepfather, I always thought of him as Daddy.

From "The Color of Water: A Black Man's Tribute to His White Mother" by James McBride