A spirit shown by royal followers in battle (9)
I believe the answer is:
agincourt
'battle' is the definition.
(Agincourt is an example)
'a spirit shown by royal followers' is the wordplay.
'spirit' becomes 'gin' (alcoholic spirit).
'shown by' is a charade indicator (letters next to each other).
'royal followers' becomes 'court' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a'+'gin'+'court'='AGINCOURT'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for agincourt that I've seen before include "Battle in Hundred Years' War" , "English victory in 1415" , "where Henry met Constable" , "English-French battle" , "Henry V's battle" .)