Prepared to fight (3-2)
I believe the answer is:
set-to
'fight' is the definition.
(I know that set-to is a type of fight)
'prepared to' is the wordplay.
'prepared' becomes 'set' (set up or ready).
'set'+'to'='SET-TO'
(Other definitions for set-to that I've seen before include "Brief fight" , "Disagreement, fight" , "Scrap" , "brush with violence?" , "Fight, argument" .)