Unsure of Parisian cutting corners (10)
I believe the answer is:
indecisive
'unsure' is the definition.
(thesaurus)
'of parisian cutting corners' is the wordplay.
'of parisian' becomes 'de' ('of' in French).
'cutting' becomes 'incisive' (synonyms).
'corners' means one lot of letters goes inside another (to corner can mean to trap).
'de' placed within 'incisive' is 'INDECISIVE'.
(Other definitions for indecisive that I've seen before include "on the fence" , "Vacillating" , "Not settling an issue" , "Dithery" .)