Definition of infallible

• 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.