indocible

From Latin indocibilis. See in- (“not”) +‎ docible.

indocible (comparative more indocible, superlative most indocible)

1. Incapable of being taught, or not easily instructed; dull in intellect; intractable.
   • 1630–1634, Joseph Hall, “[Occasional Meditations, […]] On the Sight of a Bladder.”, in Josiah Pratt, editor, The Works of the Right Reverend Father in God, Joseph Hall, D.D. […], volume VI (Devotional Works), London: […] C[harles] Whittingham, […]; for Williams and Smith, […], published 1808, →OCLC, page 200:

     Let him alone, till time and ill example have hardened him; till he be settled in a habit of evil, and contracted and clung together with sensual delights; now he becomes utterly indocible.

• indocibleness