Stubborn old bishop rude at turns (8)
I believe the answer is:
obdurate
'stubborn' is the definition.
(obdurate means stubborn or obstinate)
'old bishop rude at turns' is the wordplay.
'old' becomes 'o' (abbreviation).
'bishop' becomes 'B' (chess abbreviation).
'turns' is an anagram indicator.
'rude'+'at'='rudeat'
'rudeat' with letters rearranged gives 'durate'.
'o'+'b'+'durate'='OBDURATE'
(Other definitions for obdurate that I've seen before include "Hard-hearted" , "Stubborn, unpersuadable" , "Implacable" , "Obstinate and unrepentant" , "Stubborn and unyielding" .)