an offence against moral or religious law or divine commandments
Usually taken to refer to moral (and especially sexual) misconduct, the term ‘sin’ implies a state in which a person has chosen to separate himself or herself from God. Since breaking religious or moral rules is believed to be a sign of such separation, sin has come to refer more generally to the action rather than the spiritual state — Dr Mel Thompson
an action considered highly reprehensible
It's a sin to waste food
live in sin
to cohabit
sinless adj
sinlessly adv
sinlessness noun
[Old English synn]