Protestor to criticise distinctive TV feature (9)
I believe the answer is:
dissident
'protestor' is the definition.
(thesaurus)
'criticise distinctive tv feature' is the wordplay.
'criticise' becomes 'diss' (to diss is to criticise or insult).
'distinctive tv feature' becomes 'ident' (an TV ident identifies the channel you're watching).
'diss'+'ident'='DISSIDENT'
'to' acts as a link.
(Other definitions for dissident that I've seen before include "Political nonconformist" , "Rebel, protestor" , "One opposed to official policy" , "Protester" , "Insets did for one who opposes authority" .)