Don't buy, that is, from shifty Leslie (4)
I believe the answer is:
sell
'don't buy' is the definition.
The definition and answer can be both to do with ownership as well as being verbs in their base form.
Maybe there's an association between them I don't understand?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for sell that I've seen before include "Decorative edging" , "disappointment?" , "Vend, auction off" , "Give up for a price" , "Trade" .)