Battle rejoined later in court (8)
I believe the answer is:
waterloo
'battle' is the definition.
(1815 battle)
'rejoined later in court' is the wordplay.
'rejoined' indicates an anagram.
'in' is an insertion indicator.
'court' becomes 'woo' (both can mean to romance someone).
'later' anagrammed gives 'aterl'.
'aterl' going within 'woo' is 'WATERLOO'.
(Other definitions for waterloo that I've seen before include "Belgian village where Napoleon fell" , "battle in Belgium" , "Famous battle" , "Losers may meet theirs" , "Decisive defeat" .)