Deadly feud conducted with relative bitterness? (8)
I believe the answer is:
vendetta
This could be a double definition.
'deadly feud' is the first definition.
'vendetta' can be an answer for 'feud' (I've seen this before). I am not sure about the 'deadly' bit.
'conducted with relative bitterness?' is the second definition.
'vendetta' can be an answer for 'bitterness?' (thesaurus). I'm not certain of the 'conducted with relative' bit.
Can you help me to learn more?
(Other definitions for vendetta that I've seen before include "Private feud" , "Violent quarrel" , "Prolonged bitter quarrel" , "Long bitter row" , "Unremitting battle" .)