Protest new spirit (5)
I believe the answer is:
demon
'spirit' is the definition.
(I've seen this before)
'protest new' is the wordplay.
'protest' becomes 'demo' (I've seen this before).
'new' becomes 'n'.
'demo'+'n'='DEMON'
(Other definitions for demon that I've seen before include "Fallen angel" , "Skilful person" , "Familiar" , "Inspiring force" , "Evil spirit or cruel person" .)