Could apple be so thoroughly corrupt? (6,2,3,4)
I believe the answer is:
rotten to the core
'could apple be so thoroughly' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'corrupt?' is the wordplay.
I cannot quite understand how this works, but
'corrupt?' could be 'rotten' ('rotten' can be a synonym of 'corrupt') and 'rotten' is found in the answer.
The remaining letters 'tothecore' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for rotten to the core that I've seen is " A bad apple".)