Case of abetting defendant here, where Henry won (9)
I believe the answer is:
agincourt
'henry won' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'case of abetting defendant here' is the wordplay.
'case of' suggests removing the centre (like emptying a case).
'defendant here' becomes 'incourt' (I can't justify this - if you can you should give a lot more credence to this answer).
'abetting' with its middle taken out is 'ag'.
'ag'+'incourt'='AGINCOURT'
'where' is the 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" , "Battleground" , "1415 battle in the Pas-de-Calais" , "battle site" .)