Retired priest is second to identify Puccinian style (7)
I believe the answer is:
verismo
'puccinian style' is the definition.
(style of opera exemplified by Puccini)
'retired priest is second' is the wordplay.
'retired' is a reversal indicator.
'priest' becomes 'rev'.
'second' becomes 'mo' (both are short periods of time).
'rev' in reverse letter order is 'ver'.
'ver'+'is'+'mo'='VERISMO'
'to identify' is the link.
(Other definitions for verismo that I've seen before include "Italian opera movement favouring realism" , "Italian operatic style" , "Puccini's style" , "Realistic style in Italian opera" .)