infallible

Incapable of erring.

Incapable of failing; certain.

Incapable of error in expounding doctrine on faith or morals.

Not fallible in knowledge, judgment, or opinion; exempt from fallacy or liability to error; unerring.

Unfailing in character or effect; exempt from uncertainty or liability to failure; absolutely trustworthy.

Not fallible; not capable of erring; entirely exempt from liability to mistake; unerring; inerrable.

Not liable to fail, deceive, or disappoint; indubitable; sure; certain

Incapable of error in defining doctrines touching faith or morals. See Papal infallibility, under Infallibility.

Without fault or weakness; incapable of error or fallacy.

certain, sure.