Come up a slope (5)
I believe the answer is:
arise
'come up' is the definition.
('arise' can be a synonym of 'come up')
'a slope' is the wordplay.
'slope' becomes 'rise' (rise is a kind of slope**).
'a'+'rise'='ARISE'
(Other definitions for arise that I've seen before include "Originate; get up" , "Wake up or get up" , "W B Yeats: 'I will . . . . . and go now'" , "Get or stand up" , "Crop up" .)