Guilty child leaves home (6)
I believe the answer is:
nocent
'guilty' is the definition.
(nocent means harmful)
'child leaves home' is the wordplay.
'child' becomes 'innocent' (innocent can mean a child).
'leaves' indicates named letters should be taken away.
'home' becomes 'in' ('he's home' can mean 'he's in').
'innocent' with 'in' removed is 'NOCENT'.
(Other definitions for nocent that I've seen before include "Harmful" , "guilty person" .)