Accomplished Republican bribed guards (7,3)
I believe the answer is:
brought off
'accomplished' is the definition.
(to bring something off is to accomplish it)
'republican bribed guards' is the wordplay.
'republican' becomes 'r' (abbreviation).
'bribed' becomes 'bought off' (buying off is a kind of bribing).
'guards' indicates putting letters inside (inserted letters are guarded).
'r' put into 'boughtoff' is 'BROUGHT OFF'.
(Other definitions for brought off that I've seen before include "Achieved a goal" , "was substituted?" .)