Source : Webster's Revised Unabridged Dictionary (1913)

Errancy \Er"ran*cy\, n. [L. errantia.]
   A wandering; state of being in error.

Source : WordNet®

errancy
     n 1: (Christianity) holding views that disagree with accepted
          doctrine; especially disagreement with Papal
          infallibility; "he denies the errancy of the Catholic
          Church"
     2: fallibility as indicated by erring or a tendency to err
        [ant: {inerrancy}]