Forgive standard of mafia boss (6)
I believe the answer is:
pardon
'forgive' is the definition.
(I know that pardon is a more specific form of forgive)
'standard of mafia boss' is the wordplay.
'standard of' becomes 'par' (I can't justify this - if you can you should give a lot more credence to this answer).
'mafia boss' becomes 'don' (term for a mafia leader).
'par'+'don'='PARDON'
Can you help me to learn more?
(Other definitions for pardon that I've seen before include "Excuse or absolve" , "indulgence" , "Forgive, perhaps judicially" , "Forgive the polite interruption" , "Forgiveness - I beg yours" .)