Young troublemaker, ordinary figure close to delinquent lacking strength (8)
I believe the answer is:
impotent
'lacking strength' is the definition.
(impotent can mean lacking power or strength)
'young troublemaker ordinary figure close to delinquent' is the wordplay.
'young troublemaker' becomes 'imp' (term for a misbehaving child).
'ordinary' becomes 'O' (abbreviation e.g. O-Levels).
'figure' becomes 'ten' (I've seen this before).
'close to' says to take the final letters (the close/ending of).
The final letter of 'delinquent' is 't'.
'imp'+'o'+'ten'+'t'='IMPOTENT'
(Other definitions for impotent that I've seen before include "Ineffective" , "Useless" , "Mon petit may be powerless" , "Helpless, powerless" , "Powerless like mon petit" .)