Refractory, at its core, describes resistance to control, treatment, or authority. In medicine, it signifies a condition that doesn't respond to standard therapies. In materials science, it denotes a substance's ability to withstand high temperatures without melting or deforming.
More broadly, it can describe a person or an animal that is stubbornly disobedient or unmanageable. The specific nuance depends heavily on the context in which it's used, ranging from clinical resistance to a drug to willful defiance of rules or laws.
Ultimately, Refractory suggests a persistent inability or unwillingness to be affected or changed.
RESTIVE
STUBBORN PERVERSE
FRACTIOUS
DISOBEDIENT
RECALCITRANT
FURNACELINING