Obstinacy, stubbornness (13)
I believe the answer is:
intransigence
This clue is a double definition.
'obstinacy' is the first definition.
(I know that intransigence is a type of obstinacy)
'stubbornness' is the second definition.
(I know that intransigence is a type of stubbornness)
(Other definitions for intransigence that I've seen before include "Obstinacy" , "lack of flexibility" , "pigheadedness" , "Refusal to change one's opinions" , "Stubborn refusal to compromise" .)