... of copper's split, keeping the right cut (4)
I believe the answer is:
crop
'cut' is the definition.
(cropping is a kind of cutting)
'of copper's split keeping the right' is the wordplay.
I cannot really see how this works, but
'of' could be 'o' and 'o' is found in the answer.
'right' could be 'r' (abbreviation) and 'r' is located in the answer.
'copper' could be 'p' and 'p' is located in the answer.
A single letter 'c' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for crop that I've seen before include "Whip with loop instead of lash" , "(Yield from) cultivated plant" , "Yield -- trim" , "supply" , "Harvest yield" .)