Take 50% off most olives and large, white radish (5)
I believe the answer is:
mooli
'large white radish' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for mooli that I've seen before include "Radish-like root" , "Large white radish" , "root vegetable" .)