Spirit haunting a hall of justice in Battle (9)
I believe the answer is:
agincourt
'battle' is the definition.
(Agincourt is an example)
'spirit haunting a hall of justice' is the wordplay.
'spirit' becomes 'gin' (alcoholic spirit).
'haunting' is an insertion indicator (haunt can mean to visit).
'hall of justice' becomes 'court' (law court).
'a'+'court'='acourt'
'gin' placed into 'acourt' is 'AGINCOURT'.
'in' acts as a link.
(Other definitions for agincourt that I've seen before include "1415 battle in the Pas-de-Calais" , "October twenty four, 1415 battle" , "French village" , "English-French battle" , "Battleground" .)