Jack, mid-coup, obtains wound fighting (8)
I believe the answer is:
jousting
'fighting' is the definition.
(jousting is a kind of fighting)
'jack mid-coup obtains wound' is the wordplay.
'jack' becomes 'J' (playing card abbreviation).
'mid' indicates the central letters (mid- can mean the middle of something).
'obtains wound' becomes 'sting' (I am not sure about this - if you are sure you should believe this answer much more).
The middle of 'coup' is 'ou'.
'j'+'ou'+'sting'='JOUSTING'
Can you help me to learn more?
(Other definitions for jousting that I've seen before include "tilting!" , "Fighting on horseback in a tournament" .)