Flustered later in court battle (8)
I believe the answer is:
waterloo
'battle' is the definition.
(1815 battle)
'flustered later in court' is the wordplay.
'flustered' is an anagram indicator.
'in' means one lot of letters goes inside another.
'court' becomes 'woo' (both can mean to romance someone).
'later' is an anagram of 'aterl'.
'aterl' going into 'woo' is 'WATERLOO'.
(Other definitions for waterloo that I've seen before include "Napoleon's final defeat" , "song" , "Belgian battle site" , "Where Wellington defeated Napoleon" , "Tracked site" .)