Pain around slope (5)
I believe the answer is:
cramp
'pain' is the definition.
(I have seen 'Muscular pain' mean 'cramp' so perhaps 'pain' could also mean 'cramp')
'around slope' is the wordplay.
'around' becomes 'c' (abbreviation for 'circa').
'slope' becomes 'ramp' (I've seen this before).
'c'+'ramp'='CRAMP'
(Other definitions for cramp that I've seen before include "Muscle spasm" , "restraint" , "hamper" , "Involuntary muscular contraction" , "Painful muscular contraction" .)