Malevolent spirit in protest ending in disruption (5)
I believe the answer is:
demon
'malevolent spirit' is the definition.
(I've seen this in another clue)
'protest ending in disruption' is the wordplay.
'protest' becomes 'demo' (demonstration).
'ending in' says to take the final letters.
The final letter of 'disruption' is 'n'.
'demo'+'n'='DEMON'
'in' acts as a link.
(Other definitions for demon that I've seen before include "malignant spirit" , "Familiar" , "Imp" , "Bad spirit" , "Fanatic; devil" .)