The Collaborative International Dictionary of English v.0.48:

Ignoscible \Ig*nos"ci*ble\, a. [L. ignoscibilis, fr. ignoscere
   to pardon, lit., not to wish to know; pref. in- not +
   gnoscere, noscere, to learn to know. See In- not, and
   Know.]
   Pardonable. [Obs.] --Bailey.
   [1913 Webster]