Any number seen aboard punt that's leaning (4)
I believe the answer is:
bent
'that's leaning' is the definition.
(I've seen this in another clue)
'any number seen aboard punt' is the wordplay.
'any number' becomes 'n' (mathematical symbol for an unspecified number).
'seen aboard' indicates putting letters inside.
'punt' becomes 'bet' (punt can mean a bet).
'n' going within 'bet' is 'BENT'.
(Other definitions for bent that I've seen before include "Out of shape, curved" , "Dishonest; angled" , "Propensity, preference" , "Dishonest; curved" , "Slang for dishonest or crooked" .)