*fallib*

a. [ LL. fallibilis, fr. L. fallere to deceive: cf. F. faillible. See Fail. ] Liable to fail, mistake, or err; liable to deceive or to be deceived; as, all men are fallible; our opinions and hopes are fallible. [ 1913 Webster ]

adv. In a fallible manner. [ 1913 Webster ]

n. One who accepts or maintains the dogma of papal infallibility. [ 1913 Webster ]

n. [ Cf. F. infaillibilité. ] The quality or state of being infallible, or exempt from error; inerrability. [ 1913 Webster ]

Infallibility is the highest perfection of the knowing faculty. Tillotson. [ 1913 Webster ]

Papal infallibility (R. C. Ch.), the dogma that the pope can not, when acting in his official character of supreme pontiff, err in defining a doctrine of Christian faith or rule of morals, to be held by the church. This was decreed by the Ecumenical Council at the Vatican, July 18, 1870. [ 1913 Webster ]

a. [ Pref. in- not + fallible: cf. F. infallible. ] [ 1913 Webster ]

1. Not fallible; not capable of erring; entirely exempt from liability to mistake; unerring; inerrable. Dryden. [ 1913 Webster ]

2. Not liable to fail, deceive, or disappoint; indubitable; sure; certain; as, infallible evidence; infallible success; an infallible remedy. [ 1913 Webster ]

To whom also he showed himself alive, after his passion, by many infallible proofs. Acts i. 3. [ 1913 Webster ]

3. (R. C. Ch.) Incapable of error in defining doctrines touching faith or morals. See Papal infallibility, under Infallibility. [ 1913 Webster ]

n. The state or quality of being infallible; infallibility. Bp. Hall. [ 1913 Webster ]

adv. In an infallible manner; certainly; unfailingly; unerringly. Blair. [ 1913 Webster ]