Small number rabble-rousing (8)
I believe the answer is:
sedition
'rabble-rousing' is the definition.
(thesaurus)
'small number' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'number' becomes 'edition' (edition is a kind of number).
's'+'edition'='SEDITION'
(Other definitions for sedition that I've seen before include "Action inciting rebellion" , "revolt" , "Stirring up of rebellion or disorder" , "Incitement to disorder" , "Revolution against a government" .)