Commitment shown in battle (10)
I believe the answer is:
engagement
This clue is a double definition.
'commitment' is the first definition.
(engagement is a kind of commitment)
'battle' is the second definition.
('engagement' can be a synonym of 'battle')
'shown in' is the link.
(Other definitions for engagement that I've seen before include "Appointment - conflict" , "promise of union" , "publicized by a band" , "Sort of ring" , "Date, battle, or betrothal" .)