Treatability is an antonym of untreatability.
As nouns the difference between treatability and untreatability
is that treatability
is (uncountable) the condition of being treatable while untreatability
is the state or condition of being untreatable.
Other Comparisons: What's the difference?
(uncountable) The condition of being treatable
(countable) A measure of the extent to which something is treatable
The state or condition of being untreatable.