Lady guards breeding ground! Pardon? (7)
I believe the answer is:
amnesty
'pardon?' is the definition.
(amnestying is a kind of pardoning)
'lady guards breeding ground' is the wordplay.
'lady' becomes 'amy' (I've seen this before**).
'guards' indicates putting letters inside.
'breeding ground' becomes 'nest' (I've seen this in other clues).
'amy' placed around 'nest' is 'AMNESTY'.
(Other definitions for amnesty that I've seen before include "A general pardon for offences against the state" , "General pardon, usually political" , "Dispensation" , "A general pardon as for rebels (7)" , "International organisation concerned with human rights" .)