The mafia's Top Ten? (3,4)
I believe the answer is:
hit list
'top ten?' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for hit list that I've seen before include "potential victims?" , "Those chosen for attack" , "Assassin's potential workload?" , "Successes in the music industry" , "Assassin's agenda" .)