Inerrability :: Inerrability (n.) Freedom or exemption from error; infallibility.
Inerrable :: Inerrable (a.) Incapable of erring; infallible; unerring.
Inerrableness :: Inerrableness (n.) Exemption from error; inerrability; infallibility.
Inerrably :: Inerrably (adv.) With security from error; infallibly; unerringly.