Stop cutting allowance in bank (8)
I believe the answer is:
gradient
'bank' is the definition.
(both can mean sloped ground)
'stop cutting allowance' is the wordplay.
'stop' becomes 'die' (as in a machine stopping or dying).
'cutting' indicates putting letters inside (some letters cut their way into a word).
'allowance' becomes 'grant' (both can mean money given to someone).
'die' going into 'grant' is 'GRADIENT'.
'in' acts as a link.
(Other definitions for gradient that I've seen before include "Degree of slope in a road" , "Angle of slope" , "Third OT book" , "Rise" , "Treading (anag) - slope" .)