Subdue and cut short open authority (9)
I believe the answer is:
overpower
'subdue' is the definition.
(I've seen this before)
'cut short open authority' is the wordplay.
'cut short open' becomes 'over' (I can't explain this - if you can you should give a lot more credence to this answer).
'authority' becomes 'power' (I've seen this before).
'over'+'power'='OVERPOWER'
'and' is the link.
Can you help me to learn more?
(Other definitions for overpower that I've seen before include "Get the better of" , "Subdue by greater strength or numbers" , "Subjugate" , "Crush" , "Best" .)