Questioning scoundrel, having evidence of debts (7)
I believe the answer is:
curious
'questioning' is the definition.
(similar in meaning)
'scoundrel having evidence of debts' is the wordplay.
'scoundrel' becomes 'cur' (cur can mean a despicable person).
'having' means one lot of letters go next to another.
'evidence of debts' becomes 'IOUs' (I Owe Yous, promises to pay debts).
'cur'+'ious'='CURIOUS'
(Other definitions for curious that I've seen before include "Strange - inquisitive" , "Unusual; eager to learn" , "Strange, unusual" , "Odd - inquisitive" , "Odd or eager to know" .)