Mischievous like Charlie, disrupting mass meeting (8)
I believe the answer is:
rascally
'mischievous' is the definition.
(thesaurus)
'like charlie disrupting mass meeting' is the wordplay.
'like' becomes 'as'.
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'disrupting' indicates putting letters inside (inside letters 'disrupt' the flow of outside one).
'mass meeting' becomes 'rally' ('rally' can be a synonym of 'mass meeting').
'as'+'c'='asc'
'asc' placed inside 'rally' is 'RASCALLY'.
(Another definition for rascally that I've seen is " Mischievous".)