Knight in punt that's leaning (4)
I believe the answer is:
bent
'that's leaning' is the definition.
(I've seen this in another clue)
'knight in punt' is the wordplay.
'knight' becomes 'N' (chess abbreviation).
'in' indicates putting letters inside.
'punt' becomes 'bet' (I've seen this in other clues).
'n' going within 'bet' is 'BENT'.
(Other definitions for bent that I've seen before include "Crooked; disposition" , "Sharply curved, grass" , "passion" , "Determined - sounds crooked" , "Curved, crooked" .)