A Parisian left dreadful criminal (8)
I believe the answer is:
unlawful
'criminal' is the definition.
(I've seen this before)
'a parisian left dreadful' is the wordplay.
'a parisian' becomes 'un' ('a' in French).
'left' becomes 'l' (common abbreviation).
'dreadful' becomes 'awful' (synonyms).
'un'+'l'+'awful'='UNLAWFUL'
(Other definitions for unlawful that I've seen before include "Not permitted by the state, contrary to statutes" , "Illicit" , "Illegal" , "not right" , "Criminal" .)