Odd scoundrel with debts (7)
I believe the answer is:
curious
'odd' is the definition.
(I've seen this before)
'scoundrel with debts' is the wordplay.
'scoundrel' becomes 'cur' (cur can mean a despicable person).
'with' says to put letters next to each other.
'debts' becomes 'IOUs' (promises to pay debts).
'cur'+'ious'='CURIOUS'
(Other definitions for curious that I've seen before include "Eager to learn something" , "Odd or eager to know" , "Strange - inquisitive" , "Strange, unusual" , "Eager to learn, strange" .)