Contemptible scoundrel – third of debutantes have no protection! (10)
I believe the answer is:
blackguard
'contemptible scoundrel' is the definition.
(I've seen this before)
'third of debutantes have no protection' is the wordplay.
'third of debutantes' becomes 'b' (crd letter of 'debutantes').
'have no' becomes 'lack' (I can't justify this - if you can you should believe this answer much more).
'protection' becomes 'guard' (I've seen this before).
'b'+'lack'+'guard'='BLACKGUARD'
Can you help me to learn more?
(Other definitions for blackguard that I've seen before include "Villain" , "Contemptible scoundrel" , "rogue" , "Dishonourable man" , "miscreant" .)