Grass cut by schoolchildren unlikely to go back inside (8)
I believe the answer is:
reformed
'grass cut by schoolchildren unlikely' is the definition.
I can't tell whether this definition defines the answer.
'to go back inside' is the wordplay.
'to' becomes 'for'.
'go back' becomes 'remed' (I can't explain this - if you can you should give a lot more credence to this answer).
'inside' means one lot of letters goes inside another.
'for' put inside 'remed' is 'REFORMED'.
Can you help me to learn more?
(Other definitions for reformed that I've seen before include "sort of church" , "Restored - mended one's ways" , "Changed for the better" .)