Knock a bit off approach shot (4)
I believe the answer is:
chip
'approach shot' is the definition.
(chip is a kind of approach shot)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for chip that I've seen before include "Small piece broken off something" , "Pare" , "Thin piece, of wood or potato say" , "Deep-fried potato slice" , "Small fragment, off the old block possibly" .)