Incline to wither in general (8)
I believe the answer is:
gradient
'incline' is the definition.
(I know that incline can be written as gradient)
'wither in general' is the wordplay.
'wither' becomes 'die' (I've seen this in another clue).
'in' is an insertion indicator.
'general' becomes 'Grant' (Grant is an example).
'die' going within 'grant' is 'GRADIENT'.
'to' is the link.
(Other definitions for gradient that I've seen before include "Perhaps one in ten" , "Bank" , "Level of steepness" , "Inclination" , "Treading (anag) - slope" .)