Put back equipment to get ill-gotten gains (4)
I believe the answer is:
loot
'ill-gotten gains' is the definition.
(looted or stolen items)
'put back equipment' is the wordplay.
'put back' says the letters should be written in reverse.
'equipment' becomes 'tool' (a tool is a piece of equipment).
'tool' reversed gives 'LOOT'.
'to get' is the link.
(Other definitions for loot that I've seen before include "Plunder, pillage" , "Steal (goods); money" , "Haul" , "Tool found among plunder" , "Stolen goods" .)