Overturned sack to find implement (4)
I believe the answer is:
tool
'implement' is the definition.
(I know that implement can be written as tool)
'overturned sack' is the wordplay.
'overturned' says the letters should be written backwards.
'sack' becomes 'loot' (I've seen this before).
'loot' back-to-front is 'TOOL'.
'to find' is the link.
(Other definitions for tool that I've seen before include "Cat's-paw; impress design on" , "organ" , "For example, saw" , "Maybe saw" , "Hand implement" .)