Pig-headed (9)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
obstinate
'pig-headed' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for obstinate that I've seen before include "Blindly stubborn" , "headstrong" , "Pig-headed" , "Stubborn, obdurate" , "Mulish" .)