Priest initiated groom, setting off religious carnage (6)
I believe the answer is:
pogrom
'off religious carnage' is the definition.
'pogrom' can be an answer for 'carnage' (thesaurus). I am unsure of the 'off religious' bit.
'priest initiated groom setting' is the wordplay.
'initiated' says to take the initial letters.
'setting' indicates an anagram.
The initial letter of 'priest' is 'p'.
'groom' with letters rearranged gives 'ogrom'.
'p'+'ogrom'='POGROM'
Can you help me to learn more?
(Other definitions for pogrom that I've seen before include "An organised massacre of a people" , "Organised persecution of an ethnic group" , "Organised massacre of Jews" , "Mass slaughter" , "Racial massacre" .)