refractory
noun.
lining consisting of material with a high melting point; used to line the inside walls of a furnace
Synonym: furnace lining
adj.
not responding to treatment
a stubborn infection|a refractory case of acne|stubborn rust stains
Synonym: stubborn
adj.
temporarily unresponsive or not fully responsive to a process or stimulus
the refractory period of a muscle fiber
adj.
stubbornly resistant to authority or control
a fractious animal that would not submit to the harness|a refractory child
Synonym: fractious, recalcitrant