Death parts old soldier and army volunteers in feud (8)
I believe the answer is:
vendetta
'volunteers in feud' is the definition.
'vendetta' can be an answer for 'feud' (vendetta is a kind of feud). I am unsure of the 'volunteers in' bit.
'death parts old soldier and army' is the wordplay.
'death' becomes 'end' (synonyms).
'parts' means one lot of letters goes inside another (in the sense of cuts or separates).
'old soldier' becomes 'vet' (I've seen this in another clue).
'and' is a charade indicator (letters next to each other).
'army' becomes 'TA' (abbreviation for Territorial Army).
'end' inserted into 'vet' is 'vendet'.
'vendet'+'ta'='VENDETTA'
Can you help me to learn more?
(Other definitions for vendetta that I've seen before include "Lasting feud associated with Sicily and mafia" , "intense feud" , "A bitter Italian feud" , "Prolonged bitter quarrel" , "A prolonged feud of Sicilian origin" .)