Second key cut revealed key, perhaps (8)
I believe the answer is:
skeleton
'key perhaps' is the definition.
(skeleton key)
'second key cut revealed' is the wordplay.
'second' becomes 's' (common abbreviation).
'cut' means to remove the last letter.
'revealed' becomes 'leton' (to let on about something is to reveal it).
'key' with its final letter taken off is 'ke'.
's'+'ke'+'leton'='SKELETON'
(Other definitions for skeleton that I've seen before include "structure as basis" , "Bony framework" , "Bones of a body" , "This key fits many locks" , "Possibly key" .)