refractory
re-frac-to-ry
adjective
(Of a material) resistant to heat, difficult to melt, or work with.
"Refractory bricks are used to line furnaces."
adjective
Stubbornly disobedient or unmanageable; unwilling to yield to control or treatment.
"The refractory patient refused to take his medication."
Thesaurus
Synonyms: intractable, stubborn, fractious, recalcitrant, disobedient, unresponsive, furnace lining