Definitions of refractory:

• noun:   lining consisting of material with a high melting point; used to line the inside walls of a furnace
• adjective:   not responding to treatment

  Example: "A refractory case of acne"

• adjective:   resistant to authority or control

  Example: "As refractory as a mule"

• adjective:   stubbornly resistant to authority or control

  Example: "A refractory child"

• adjective:   marked by stubborn resistance to and defiant of authority or guidance

  Example: "Everything revolves around a refractory individual genius"