Intractable, a.
Etymology: [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.
Shades of meaning
Fernald has no entry of its own for intractable; he lists it under obstinate, perverse, rebellious, restive.
Where he writes about it:
The petulant person frets, but may comply; the perverse individual may be smooth or silent, but is wilfully intractable. — from perverse
With this the metaphorical use of the word agrees, which is always in the sense of such terms as impatient, intractable, rebellious, and the like; a people restive under despotism are not disposed to "rest" under it, but to resist it and fling it off. — from restive
Synonyms
obstinateperverserebelliousrestivebalkycontrarycontumaciousdecideddetermineddisobedientdoggedfactiousfidgetyfirmfixedfractiousfretfulfriskyfrowardheadstrongheadyimmovableimpatientindomitableinflexibleinsubordinatemulishmutinousobdurateopinionatedpersistentpertinaciouspetulantrecalcitrantrefractoryresentfulresoluteresolvedrestiffrestlessseditiousskittishstubbornunconquerableuncontrollableunflinchingungovernableunmanageableunrulyuntowardunyieldingviciouswaywardwilful