Conflict involving old offensive (5)
I believe the answer is:
foray
'offensive' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'conflict involving old' is the wordplay.
'conflict' becomes 'fray' (fray is a kind of conflict).
'involving' is an insertion indicator.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'fray' going around 'o' is 'FORAY'.
Can you help me to learn more?
(Other definitions for foray that I've seen before include "Sortie" , "Raid or incursion" , "Assault" , "Sudden short attack" , "Brief incursion" .)