Dogged, unyielding (9)
I believe the answer is:
tenacious
I believe this clue is a double definition.
'dogged' is the first definition.
(I know that dogged can be written as tenacious)
'unyielding' is the second definition.
(I know that unyielding can be written as tenacious)
(Other definitions for tenacious that I've seen before include "Holding fast" , "Persevering" , "Holding or sticking firmly" , "Keeping a firm hold" , "Determined" .)