refractory

adj. 1 stubborn, unmanageable, rebellious. 2 (of a wound, disease, etc.) Not yielding to treatment. 3 (of a substance) hard to fuse or work. [latin: related to *refract]

a. Obstinate in disobedience; contumacious; stubborn; unmanageable; as, a refractory child; a refractory beast.