Five battle without a break (8)
I believe the answer is:
vacation
'break' is the definition.
(I've seen this before)
'five battle without a' is the wordplay.
'five' becomes 'V' (Roman numeral).
'battle' becomes 'action' (military action).
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'action' placed around 'a' is 'acation'.
'v'+'acation'='VACATION'
(Other definitions for vacation that I've seen before include "An American holiday" , "break" , "Leave" , "Leisure time away from work" , "Holiday period" .)