Six, openly collecting debts, are deliberately cruel (7)
I believe the answer is:
vicious
'cruel' is the definition.
(I know that cruel can be written as vicious)
'six openly collecting debts are deliberately' is the wordplay.
I cannot quite see how this works, but
'six' could be 'vi' (Roman numerals) and 'vi' is found within the answer.
'debts' could be 'ious' (promises to pay debts) and 'ious' is present in the answer.
A single letter 'c' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for vicious that I've seen before include "Deliberately harmful and savage" , "Strongly spiteful and dangerous" , "Deliberately nasty" , "Savage and strongly spiteful" , "Malicious, brutal" .)