Around convict, heap plunder (7)
I believe the answer is:
pillage
'plunder' is the definition.
('pillage' can be a synonym of 'plunder')
'around convict heap' is the wordplay.
'around' means one lot of letters goes inside another.
'convict' becomes 'lag' (I've seen this before).
'heap' becomes 'pile' ('pile' can be a synonym of 'heap').
'lag' put within 'pile' is 'PILLAGE'.
(Other definitions for pillage that I've seen before include "Sacking" , "Rob with violence" , "Loot" , "Plunder, sack" , "Violent stealing" .)