Controversial eastern cause (7)
I believe the answer is:
emotive
'controversial' is the definition.
(I've seen this before)
'eastern cause' is the wordplay.
'eastern' becomes 'e'.
'cause' becomes 'motive'.
'e'+'motive'='EMOTIVE'
(Other definitions for emotive that I've seen before include "Argumentative" , "Sensitive - controversial" , "Arousing intense feeling" , "able to get going" , "Arousing deep feeling" .)