Motherless man beset by sinfulness? (5)

I believe the answer is:

vince

I'm a little stuck... Click here to teach me more about this clue!

'sinfulness?' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.

'motherless man beset by' is the wordplay.
'motherless' becomes 'vice' (I can't justify this - if you can you should give a lot more credence to this answer).
'man' becomes 'n' (knight, a man in chess).
'beset by' indicates putting letters inside ('beset' could historically mean 'cover').
'vice' placed around 'n' is 'VINCE'.

Can you help me to learn more?

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.