The Catholic Church has defined criteria for when a sin is a mortal sin:

  1. The sin is grave.
  2. It's committed with full knowledge of the sin and its gravity.
  3. It's committed with deliberate and complete consent.

However, many of the sins that the Church has at some point described as grave are on a spectrum of severity and must be subjectively judged. E.g., cheating at a game can be grave if it's severe enough (how severe is that?), wages have to be just or else underpaying someone counts as grave (how does one know the threshold?), hatred and envy are grave if one wishes great harm to another person (how great? does one have to wish for the harm to actually happen, or just enjoy the thought?), lying can be grave depending on details, and so on.

My question is, how can one know when the threshold is met and a sin is grave? Is this enforced or defined in any regulating, normative way, or is it just left to the opinions of the clergy?

2 Answers 2


How defined is the threshold of graveness for mortal sins? (Catholicism)

As with such matters of conscience, there will always exist some wiggle room in the definition here.

Interesting question, as threshold as to what constitutes grave matter is much more than simply listing a number of actions that constitutes as mortal sin. There may be extenuating circumstances that may diminish the nature of a particular action that would make it normally a serious sin. Circumstances could theoretically in some situations, mitigate any culpability all together.

For example, a person who does not have the full use of their reason can not sin seriously.

Not every violation of the Ten Commandments constitutes a mortal sin. For instance, a 6 year-old child stealing a nickel from a rich man might violate the commandment to "not steal", but it is not mortal, because it is not grave matter.

There are examples of such stories, even in the lives of some of the saints.

The Catechism of the Catholic Church defines grave mater as follows:

1858 Grave matter is specified by the Ten Commandments, corresponding to the answer of Jesus to the rich young man: "Do not kill, Do not commit adultery, Do not steal, Do not bear false witness, Do not defraud, Honor your father and your mother." The gravity of sins is more or less great: murder is graver than theft. One must also take into account who is wronged: violence against parents is in itself graver than violence against a stranger.

We must also remember that the Ten Commandments is not an exhaustive list of mortal sins.

So, while it is almost impossible to come up with a definitive list of sins that are mortal, here are some that should be confessed (pardon the randomness, I did it off the top of my head and from a few other lists):

  • Murder

  • Blasphemy

  • Idolatry

  • Adultery

  • Pride

  • Abortion

  • Rape

  • Despair in God's mercy

  • Occult activity

  • Superstition

  • Divination / Using Magic

  • Illegal Drug Use

  • Intentionally getting drunk

  • Defiant disobedience of your parents, for non-adult children

  • Wanton destruction on another's property

  • Lustful thoughts that are dwelt upon

  • Prostitution

  • Fornication

  • Pornography / Masturbation

  • Homosexual Acts

  • Incest

  • Theft

  • Greed

  • Envy

  • Abuse of the Poor / not giving to the poor

  • Defrauding others of what they are due

  • Serious Lies / Lying under oath (perjury)

  • Jealousy

  • Laziness

  • Bad-mouthing others / gossip

  • Missing Mass on Sunday or a Holy Day

  • Presumption of God's forgiveness

  • Anger that has no justification

  • Hatred of others

  • Euthanasia

  • Grave scandal

  • Heresy

  • Apostasy / Schism

  • Gluttony

  • Extortion

  • Terrorism

  • Divorce and re-marriage

  • Spiritual Sloth


Often we have questions about the seriousness of our action and doubts arise as to the seriousness of something we have done. Thank God, we as Catholics have the sacrament of confession. In such situations, it is best to humbly make a good confession and explain the situation to a priest, who is trained to deal in this matter.

In the moral theology of Catholicism, a mortal sin requires that all of the following conditions are met:

  1. Its subject matter must be grave. (The term "grave sin" is used at times to indicate grave matter, and at times to indicate mortal sin. But it always remains true that the following two conditions are requisite for mortal sin.)

  2. It must be committed with full knowledge (and awareness) of the sinful action and the gravity of the offence.

  3. It must be committed with deliberate and complete consent.

With respect to a person's full knowledge of a certain act being a grave sin, the Catholic Church teaches that "unintentional ignorance can diminish or even remove the imputability of a grave offense. But no one is deemed to be ignorant of the principles of the moral law, which are written in the conscience of every man. The promptings of feelings and passions can also diminish the voluntary and free character of the offense, as can external pressures or pathological disorders (mental illness). Sin committed through malice, by deliberate choice of evil, is the gravest." Furthermore, Catholic teaching also holds that "imputability and responsibility for an action can be diminished or even nullified by ignorance, inadvertence, duress, fear, habit, inordinate attachments, and other psychological or social factors." In this regard, a sin committed while one is inebriated may lack the awareness and consent necessary for the sin to be mortal. But when one becomes aware of the danger of excessive drink, such drinking itself becomes a serious matter.

Grave sins should not to be confused with the seven deadly sins, which are so called because they lead to other sins; they are not necessarily grave sins.

Mortal sins are called "grave sins" under the Code of Canon Law due to the "grave" nature of all mortal sins, and the terms are used there interchangeably. This does not deny the distinction given above, that there may be grave matter but not a grave sin if the other conditions of knowledge and freedom are not present.

Mortal sins must be confessed by naming the specific offence along with how many times it was committed. Mention of how long since one's last confession is to establish whether one is truly penitent – has a purpose of amendment.

It is not necessary to confess venial sins although they may be confessed, a practice that began with the Irish monks around the 12th century. Venial sins are all sins that are not mortal. The Church encourages frequent, intelligent use of the sacrament of confession even if a person has only venial sins, in view of the benefits that might be derived. Mortal Sin (Catholic Encyclopaedia)


The fact that the gravity of sins is on a spectrum means, intrinsically, that you will not be able to tell precisely where the cross from venial to mortal sin takes place. Some actions are clearly defined as always grave in and of themselves, but for those that exist on this spectrum (theft, for instance, or gluttony), it takes prudential judgement and an honest examination of conscience.

It is obvious that thefts of large amounts are mortally sinful. Every Catholic would agree that stealing $1 million dollars is a mortal sin. Probably just about every well-formed Catholic would also agree that, barring severe malice, stealing $1 is a venial sin. Stealing $500,000 is probably still mortal, but what about stealing $100? We would probably agree that stealing $100,000 is mortal. What about $1000? Maybe so. Maybe you thought $100 was grave enough. Maybe you didn't.

It's tough to know where exactly that line is. If you commit a sin that is on this spectrum, you should confess it to be safe, because you want to make sure you are confessing all mortal sins.

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