Sacks turned over as something to sit on (5)
I believe the answer is:
stool
'as something to sit on' is the definition.
I can't tell whether this defines the answer.
'sacks turned' is the wordplay.
'sacks' becomes 'loots' (to sack is to loot or pillage).
'turned' shows that the letters should be reversed in order.
'loots' reversed gives 'STOOL'.
'over' acts as a link.
Can you help me to learn more?
(Other definitions for stool that I've seen before include "Simple seat" , "item of furniture here" , "Three-legged backless seat" , "place butt on one?" , "Small seat" .)