Unfortunately hard copy admits large and small secret (9)

'unfortunately' is the definition.
Both the definition and answer are adverbs.
Maybe there's an association between them I don't understand?

'hard copy admits large and small secret' is the wordplay.
I cannot really understand how this works, but
'hard' could be 'h' (abbreviation used in pencil classifications) and 'h' is present in the answer.
'large' could be 'l' (eg in clothes sizes) and 'l' is located in the answer.
'copy' could be 'ape' (ape can mean to copy or imitate) and 'ape' is found within the leftover letters.
'small' could be 's' (abbreviation - e.g. clothes size) and 's' is found within the answer.
'secret' could be 'sly' (I've seen this in other clues) and 'sly' is found within the answer.
No letters remain.
This explanation may well be incorrect...

Can you help me to learn more?