Closeness of rugby forward, one abandoning sin (11)

'closeness' is the definition.
(propinquity means closeness or proximity)

'rugby forward one abandoning sin' is the wordplay.
I cannot really see how this works, but
'forward' could be 'prop' (both can mean a rugby player) and 'prop' is found in the answer.
'one' could be 'i' (Roman numeral) and 'i' is located in the answer.
This may be the basis of the clue (or it may be nonsense).

'of' acts as a link.