Copy of will must support oddly free criminal (9)
I believe the answer is:
reprobate
'criminal' is the definition.
(I've seen this before)
'copy of will must support oddly free' is the wordplay.
'copy of will' becomes 'probate' (a legal copy of someone's will).
'must support' says to put letters next to each other (I've seen this in other clues).
'oddly' indicates alternate letters (letters in the odd-numbered positions are used).
The alternate letters of 'free' are 're'.
'probate' after 're' is 'REPROBATE'.
(Other definitions for reprobate that I've seen before include "Berate pro, being an unprincipled person" , "Rascal" , "Sinner" , "Profligate" , "scoundrel" .)