The Collaborative International Dictionary of English v.0.48:

Intractable \In*tract"a*ble\, a. [L. intractabilis: cf. F.
   intraitable, formerly also intractable. See In- not, and
   Tractable.]
   Not tractable; not easily governed, managed, or directed;
   indisposed to be taught, disciplined, or tamed; violent;
   stubborn; obstinate; refractory; as, an intractable child.

   Syn: Stubborn; perverse; obstinate; refractory; cross;
        unmanageable; unruly; headstrong; violent; ungovernable;
        unteachable. -- In*tract"a*ble*ness, n. --
        In*tract"a*bly, adv.
        [1913 Webster]

WordNet (r) 3.0 (2006):

intractably
    adv 1: in an intractable manner