English Dictionary

Not fallible; not capable of erring; entirely exempt from liability to mistake; unerring; inerrable.
Source : opted (79409)  - auto

Not liable to fail, deceive, or disappoint; indubitable; sure; certain; as, infallible evidence; infallible success; an infallible remedy.
Source : opted (79410)  - auto

Incapable of error in defining doctrines touching faith or morals. See Papal infallibility, under Infallibility.
Source : opted (79411)  - auto