To develop a definition of "sin" requires an understanding of the origin of sin, which can be sourced at the very beginning of human beings.

The apostle Paul highlights this momentous event with a chiasm that focuses on "judgment arose from one transgression resulting in condemnation" (Rom 5:12-21).

"Therefore, just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all sinned."

The forbidden fruit provided knowledge Adam and Eve were not supposed to have, and it altered their human nature (Gen 3:7).

Because the judgement of death is accorded to all human beings, the legal status of all human beings has changed from innocent to guilty; this reflects the alteration of human nature caused by the forbidden fruit.

This provides the first indication that sin is determined by God Himself and His very nature (Rom 4:14-20).

Understanding God's view of sin provides another perspective of God. The legal standard by which righteousness is determined by whether one obeys and follows God's word.

Sin is a transgression of God's word or rebellion against God, and Jesus describes sinners as "lawless." Paul places an emphasis on lawless by contrasting sin with righteousness.

As a real Being who exists, God is set apart from sin and anything profane; there is no moral standard or authority outside of or above Him. God's word demonstrates that God Himself is the moral standard and authority of moral goodness.

Set within a legal framework, as demonstrated by the Law of Moses, sin requires a legal remedy. One consequence of sin is judicial punishment and the other is one of mercy.

When Jesus speaks of sin as a noun, He almost always spoke of it in the context of forgiveness!

But if Eve committed the first sin, how come Eve's personal act of disobedience was attributed to Adam?

To learn more, see:

Did God create sin? Where did sin come from?

Sin is a Transgression of God's Law / Moral Standard