I’ve heard sin defined as falling short or missing the mark. In my opinion the definition of sin is simple and straightforward. Sin is breaking the law. Romans 7:7, 1 John 3:4.
You’ve probably heard that someone is above the law when the law does not seem to apply to them. I believe someone is above the law as long as they don’t break it. You no longer want to be under the law in the New Testament, fine – don’t break it.
Hebrews 10:16-17 KJV This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them; [17] And their sins and iniquities will I remember no more.