Effect produced by mischievous child in front of a court (6)
I believe the answer is:
impact
'effect' is the definition.
(impact is a kind of effect)
'mischievous child in front of a court' is the wordplay.
'mischievous child' becomes 'imp' (I've seen this before).
'in front of' says to put letters next to each other.
'court' becomes 'ct'.
'imp'+'a'+'ct'='IMPACT'
'produced by' acts as a link.
(Other definitions for impact that I've seen before include "Bear upon" , "The force of one body against another" , "Crash" , "Forceful striking" , "Repercussions" .)