Hike up slope that overshadows area (5)
I believe the answer is:
raise
'hike up' is the definition.
(I've seen this in another clue)
'slope that overshadows area' is the wordplay.
'slope' becomes 'rise' (rise is a kind of slope).
'that overshadows' is an insertion indicator (the inserted letter is smothered or overshadowed).
'area' becomes 'a' (maths abbreviation).
'rise' going around 'a' is 'RAISE'.
(Other definitions for raise that I've seen before include "What a poker player might do" , "Bring up - an increase in pay" , "Lift up or rear" , "Cultivate by growing" , "Exalt" .)