Dig your heels in litter (6)
I believe the answer is:
'litter' is the definition.
(I've seen this in another clue)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for refuse that I've seen before include "Trash" , "Junk" , "Waste, garbage" , "'Deny, turn down (6)'" , "Turn down - rubbish" .)