Sullen Ed bashed, beaten for such obstinacy (4-10)

I believe the answer is:

bull-headedness

'obstinacy' is the definition.
(being bull-headed is being obstinate)

'sullen ed bashed beaten' is the wordplay.
'beaten' indicates anagramming the letters (letters beaten up or destroyed).
'sullen'+'ed'+'bashed'='sullenedbashed'
'sullenedbashed' is an anagram of 'BULL-HEADEDNESS'.

'for such' is the link.

I've seen this clue in The Telegraph.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.