Child grasps right and wrong (4)
I believe the answer is:
tort
'wrong' is the definition.
(legal term)
'child grasps right' is the wordplay.
'child' becomes 'tot' (term for a young child).
'grasps' means one lot of letters goes inside another (inserted letters are held or grasped).
'right' becomes 'r' (common abbreviation).
'tot' going around 'r' is 'TORT'.
'and' is the link.
(Other definitions for tort that I've seen before include "Private or civil wrong open to damages" , "Small tropical fish" , "Legal wrongdoing" , "Trot after legal wrong liable to damages" , "Trot to get legal wrong" .)