Sin or mistake (5)

I believe the answer is:

error

'mistake' is the definition.
(I know that mistake can be written as error)

'sin or' is the wordplay.
'sin' becomes 'err' (to sin is to err morally).
'err'+'or'='ERROR'

(Other definitions for error that I've seen before include "Faulty judgement" , "Slip-up" , "Bloomer, blunder" , "Boo-boo" , "Mistake from terrorist" .)

I've seen this clue in The Sun and The Globe and Mail.

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