Not tractable; not easily governed, managed, or directed; indisposed to be taught, disciplined, or tamed; violent; stubborn; obstinate; refractory; as, an intractable child.

not tractable; difficult to manage or mold; "an intractable disposition"; "intractable pain"; "the most intractable issue of our era"; "intractable metal"

Difficult to alleviate, remedy, or cure; for example, intractable seizures are difficult to control with the usual antiepileptic drug therapy.

about 20 percent of people with epilepsy will continue to experience seizures even with the best available treatment.

describes a condition that does not respond to treatment

resistant to normal treatment methods.

Unstoppable. For example, intractable pain.

In complexity theory, referring to a problem with no efficient means of deriving a solution.