What is Sin?

Westminster Shorter Catechism Question #14

What is Sin?

Sin is any want of conformity unto, or transgression of, the law of God.

Leviticus 5:17 And if a soul sin, and commit any of these things which are forbidden to be done by the commandments of the LORD; though he wist it not, yet is he guilty, and shall bear his iniquity.

James 4:17  Therefore to him that knoweth to do good, and doeth it not, to him it is sin.

1 John 3:4  Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law.