A man with common sense holds one to be shocking (7)
I believe the answer is:
Here is my best explanation:
'be shocking' is the definition.
'a man with common sense holds one' is the subsidiary indication.
'a man' becomes 'he' (**).
'with' is a charade indicator (letters next to each other).
'common sense' becomes 'nous' (nous is a kind of common sense).
'holds' indicates putting letters inside.
'one' becomes 'i' (roman numeral).
'henous' placed around 'i' is 'heinous'.
'to' is the link.
(Other definitions for heinous that I've seen before include "Iniquitous", "Shocking (offence)", "Utterly wicked", "Utterly odious (crime)", "Extremely evil", "Execrable", "Very wicked, maybe in-house", "Appalling (crime)", "Atrocious" and "Extremely wicked".)