The fact that atheists are terrified of the word sin is as much proof of God as the fact that atheists curse Christ is. The reason for that is that the word "sin" implies guilt and judgment. Otherwise there is no reason for atheists to avoid the word like the plague.

But since atheists are very predictable, they'll either claim that they have no problem with the word "sin", even though they've made these comments about the word:

1) The word sin is a Christian concept
2) There's no such thing as sin
3) Prove that sin exists

or they'll claim that by admitting they sin, that is admitting they believe in God. But they have no problem saying any other word in Christianity. So either way, they avoid the word because they feel judged by it. And rightly so because they are being judged by God which is why they avoid the word. And if you avoid it because you don't believe in sin, then why can you use the word "zeus" when you don't believe in zeus?

So your fear of the word is very telling indeed. But I got news for you; word games don't make God go away, nor do they make you any less guilty. But the avoidance of the word "sin" is what proves that you know that God exists.

But to try to win the argument, you might admit you sin. If so, then what do you do with your sins? Do you keep on justifying them? If so, then why do you think there should be no hell? Or do you ask for forgiveness for them? If so, who can take them away from you? Oh some people might not hold your sins against you, but how can they make them go away?