sin

sin an immoral act considered to be a transgression against divine law; an act regarded as a serious or regrettable fault, offence, or omission. The word is recorded from Old English (in form synn), and is probably related to Latin sons, sont- ‘guilty’.
it's a sin to steal a pin proverbial saying, late 19th century; meaning that even if what is stolen is of little value, the action is still wrong.
the sin against the Holy Ghost in theological debate, the only sin which may be beyond forgiveness, as indicated in the words of Jesus in Matthew 13:32. In extended modern usage, the phrase may be used for the one thing in a particular context which is seen as beyond toleration.
sin-eater someone traditionally hired to take upon themselves the sins of a deceased person by means of food eaten beside the dead body; the term is recorded from the mid 17th century, in Remains of Gentilism and Judaism by the antiquary John Aubrey (1626–97).

See also charity covers a multitude of sins, Satan rebuking sin, seven deadly sins.