Sin

Etymology of sin

OE synn for "moral wrongdoing, injury, mischief, enmity, feud, guilt, crime, offense against God, misdeed"

• from PIE *snt-ya-, forming *es-ont- for "becoming"
  • in Germanic language groups, took on meaning of "it is true". as in "the sin is real"

Forgiveness of sin

• CCC 431:

"Because sin is always an offences against God, only he can forgive it"

Origin of sin in man

For from the heart come evil thoughts, murder, adultery, unchastity, theft, false witness, blasphemy. (Mt 15:19)

Types of sin

St. Paul on sins or "works of the flesh":

Now the works of the flesh are obvious: immorality, impurity, licentiousness, idolatry, sorcery, hatreds, rivalry, jealousy, outbursts of fury, acts of selfishness, dissensions, factions (Gal 5:19-20)

From CCC 1853:

Sins can be distinguished according to their objects, as can every human act; or according to the virtues they oppose, by excess or defect; or according to the commandments they violate. They can also be classed according to whether they concern God, neighbor, or oneself; they can be divided into spiritual and carnal sins, or again as sins in thought, word, deed, or omission. The root of sin is in the heart of man, in his free will, according to the teaching of the Lord: "For out of the heart come evil thoughts, murder, adultery, fornication, theft, false witness, slander. These are what defile a man." But in the heart also resides charity, the source of the good and pure works, which sin wounds.

which we can organize as

Classification	Types
distinguish sins	by their objects by the virtues they oppose by the Commandments they violate
sins as	against God against neighbor against oneself
types of	spiritual carnal
location of	in thought in word deeded omissions