Battle developing later in court (8)
I believe the answer is:
waterloo
'battle' is the definition.
(I've seen this before)
'developing later in court' is the wordplay.
'developing' indicates anagramming the letters.
'in' means one lot of letters goes inside another.
'court' becomes 'woo' ('woo' can be a synonym of 'court'**).
'later' is an anagram of 'aterl'.
'aterl' placed within 'woo' is 'WATERLOO'.
(Other definitions for waterloo that I've seen before include "Where Wellington defeated Napoleon" , "Heavy defeat" , "Belgian battle site" , "Napoleon's 1815 defeat" , "Meet one's - -" .)