Took in both sides in court defeat (8)
I believe the answer is:
waterloo
'defeat' is the definition.
(I know that waterloo is a type of defeat)
'took in both sides in court' is the wordplay.
'took in' becomes 'ate' (take in can mean to eat).
'both sides' becomes 'RL' (abbreviation for left and right).
'in' means one lot of letters goes inside another.
'court' becomes 'woo' (both can mean to romance someone).
'ate'+'rl'='aterl'
'aterl' going into 'woo' is 'WATERLOO'.
(Other definitions for waterloo that I've seen before include "Final challenge" , "London railway terminus" , "The last battle" , "Belgian battle site" , "Belgian village where Napoleon fell" .)