Wikipedia has an article on Sin (with, of course, links to related articles) that might be as good a starting place as any for what you’re looking for.
I did some on-my-own searching on the world wide web and found this: NameBright - Coming Soon.
Check it out! It’s an example of sin!
OK. So, drinking until you’re dead is a sin, because, well, drinking too much can literally kill you.
But then… even a wise atheist would know that one should not drink like crazy and be so subjected to peer pressure. Seriously, what kind of idiot would drink himself to death?
I suppose ‘sin’ can be summarized to one word: brainless, thoughtless things that people do. These brainless, thoughtless things that people do may be “against God”, but really they provide more harm to the people who do them. Therefore, it’s a sin to commit sin, and it’s a sin to be a sinner.
Does anybody know what is the criteria for being a sinner? How many sins does one have to commit before officially becoming a sinner?
Sin is a religious concept. Therefore, each religion will have its own set of definitions.
It simply isn’t meaningful to ask “How many sins does one have to commit before officially becoming a sinner?”.
It *might *be meaningful to ask “How many sins does a member of *this *particular chapter of *that *particular denomination of *this other *particular religion one have to commit before officially becoming a sinner in the eyes of his/her fellow parishioners?”. Then again for less doctrinal churches it might not be a meaningful question at all since the congregants’ opinions would be all over the map. And even in a very doctrinaire church the rank and file opinion will probably differ significantly from that of their clergy as well.
Yes, the term is sometimes used in secular contexts, just like so many other nominally Christian ideas have found their way into mainstream Western culture. But it sounds like you’re not really interested in the secular borrowing / misuse of this concept.
According to orthodox Christian teachings all living persons are sinners, though there is some disagreement about whether the term applies to children before they become accountable for their actions. In Catholic teaching the more important distinction is between those in a state of mortal sin and those who are not. A mortal sin must be a serious matter, done with conscious choice, and done with the knowledge that it is a mortal sin. One a person commits a mortal sin, they remain in a state of mortal sin until they genuinely feel remorseful, confess the sin, and perform a penance if necessary.
My favorite definite of sin, by far, is the one used by Lazarus Long in Robert Heinlein’s novel:
Not being a person of faith, and not believing in ‘sin’ in the supernatural sense (i.e. it’s a sin because God/ says it is), this simple tool is the best litmus I’ve found.
My favorite thing I ever read for a college philosophy class was the Euthyphro dialogue because it not only expressed things I’d felt about “why is that a sin?”, but had expressed them thousands of years before I was born (and centuries before Jesus was born). Socrates’ question “Is the pious loved by the gods because it is pious, or is it pious because it is loved by the gods?” is easily flipped to “Is sin hated by the gods because it’s sinful, or is it sinful because it’s hated by the gods?” Disavowing the arbitrary “It’s a pet peeve of God/the gods/whoever” (what if tomorrow the gods decide that adultery is okay but they cannot stand dating before you’re 30- who will know/how will they get that info out/what does it mean for people who are under 30 and married?/etc." nature of the latter, and in my case and that of many others here disavowing supernatural belief systems in general, Heinlein’s as the most merit.
The Book of James has a definition that I’ve always kind of liked;
**James 4:17 KJV **
By this definition sin could be said to be subjective. If one has no moral concept of good and evil one is incapable of sinning.
And yet, the Seven Deadly Sins (wrath, greed, sloth, pride, lust, envy, and gluttony) are deadly primarily to the sinner, though there may well be some collateral damage. In that, they’re like addictions—one could even argue that they are addictions. They’re deadly because they have a tendency to consume a person, to spiritually deaden a person.

What counts as a ‘sin’?
Nothing.
There are no gods and all religious definitions of human behavior are false.
What counts is whether an act is immoral. Meaning, whether it results in damaging the welfare of the social group, or society in general.
Morality is a code of behavior that human beings agree to, so that they can preserve their life and independent way of living.
Acts are immoral, but they are not sinful. There are no spirits or gods.
Is committing a sin just an inevitable fact of life?
Yes, because human beings are naturally predisposed to sin.

All the ghastly (but mostly, just sexual) things you love to do, when done by somebody else.
– Paraphrased (loosely) from Harry Browne, How I Found Freedom in an Unfree World
Asceticism has so influenced the concept of sin that ‘sinful’ has come to mean pleasurable in circumstances. e.g. “This cake is so good it’s sinful”.
We are all sinners! It is a fact that we are born with a sinful nature. We have a spiritual malady (human condition) that can been lessened, not cured, by a willingness to grow along spiritual lines. We demonstrate this willingness through the seeking of God. “seek and you shall find” is the applicable qoute. Be not fooled, we will be judged at the end by our seeking and our progress and not by the absence of sin because our sinful nature can only be made better via the seeking and not arrested. The biggest obstacle will always be our pride and unfounded fear. Ego smashing and courage are required to be routinely practiced if we are to seek to satisfy God!

We are all sinners!
I’m not.
And I don’t need no forgiveness, neither.

Atheists, by definition, are incapable of sin. This makes them superior to believers.
Only believers believe this, of course, so they have to believe it’s not true.
That’s the only rational thing that can be said about sin.
Atheists are not incapable of sin. The fact that they not acknowledge sin does not make them sinless. Moammar Ghaddafi did what he did because he believed he was above laws and beyond morality.

The Book of James has a definition that I’ve always kind of liked;
**James 4:17 KJV **
By this definition sin could be said to be subjective. If one has no moral concept of good and evil one is incapable of sinning.
It’s important to separate amorality from immorality.

Nothing.
There are no gods and all religious definitions of human behavior are false.
What counts is whether an act is immoral. Meaning, whether it results in damaging the welfare of the social group, or society in general.
Morality is a code of behavior that human beings agree to, so that they can preserve their life and independent way of living.
Acts are immoral, but they are not sinful. There are no spirits or gods.
With no absolute basis for mortality, human cleverness subverts it instantly.

We are all sinners! It is a fact that we are born with a sinful nature. We have a spiritual malady (human condition) that can been lessened, not cured, by a willingness to grow along spiritual lines. We demonstrate this willingness through the seeking of God. “seek and you shall find” is the applicable qoute. Be not fooled, we will be judged at the end by our seeking and our progress and not by the absence of sin because our sinful nature can only be made better via the seeking and not arrested. The biggest obstacle will always be our pride and unfounded fear. Ego smashing and courage are required to be routinely practiced if we are to seek to satisfy God!
This is one of the most evil ideas I’ve ever encountered. People are not, inherently, good or evil. To consider evil to be the “human condition” is a sin.

Atheists are not incapable of sin. The fact that they not acknowledge sin does not make them sinless. Moammar Ghaddafi did what he did because he believed he was above laws and beyond morality.
What does sin have to do with morality?
“Sin lies only in hurting other people unnecessarily. All other “sins” are invented nonsense. (Hurting yourself is not sinful—just stupid.)”
Most Dopers will recognize the source.

This is one of the most evil ideas I’ve ever encountered. People are not, inherently, good or evil. To consider evil to be the “human condition” is a sin.
Then how do you explain all the evil in the world?

What does sin have to do with morality?
That depends on what you think morality is. Is it something you can use to remind others how rotten they are, or is it something that indicates your own character, as well?
Atheist morality is all about pointing out the sins of others while insisting that sin doesn’t apply to you.