- (a.) Not fallible; not capable of erring; entirely exempt from liability to mistake; unerring; inerrable.
- (a.) Not liable to fail, deceive, or disappoint; indubitable; sure; certain; as, infallible evidence; infallible success; an infallible remedy.
- (a.) Incapable of error in defining doctrines touching faith or morals. See Papal infallibility, under Infallibility.