Climb; upward slope (6)
I believe the answer is:
ascent
I believe this is a double definition.
'climb' is the first definition.
(I know that climb can be written as ascent)
'upward slope' is the second definition.
(I've seen this in another clue)
(Other definitions for ascent that I've seen before include "A rise in status; climb" , "The climbing of a peak" , "Upwards motion" , "Enacts in climb" , "Upward slope" .)