Sack the lot, hiding nothing (4)
I believe the answer is:
loot
'sack' is the definition.
(I've seen this before)
'the lot hiding nothing' is the wordplay.
'hiding' is an insertion indicator.
'nothing' becomes 'o' (looks like zero - 0).
'lot' going around 'o' is 'LOOT'.
(Other definitions for loot that I've seen before include "Tool found among plunder" , "Stolen goods" , "Booty; sack" , "Burglar's takings - pillage" , "Haul" .)