Prepare to fire with action that's now illegal (9)

I believe the answer is:
cockfight
'now illegal' is the definition.
I can't tell whether this definition defines the answer.
'prepare to fire with action' is the wordplay.
'prepare to fire' becomes 'cock' (as in cocking a gun).
'with' means one lot of letters go next to another.
'action' becomes 'fight' (fight is a kind of action).
'cock'+'fight'='COCKFIGHT'
'that's' is the link.
Can you help me to learn more?
(Other definitions for cockfight that I've seen before include "struggle between birds" , "Violent contest between birds" , "in which feathers will fly" , "Illegal contest of birds" , "Battle as between roosters" .)
