Sin is an Act
“In the Torah, sin is something more than a transaction in the soul, or even an act of wrongdoing narrowly conceived. It is an act in the wrong place. It disturbs the moral order of the world. The words for sin – chet and avera – both have this significance. Chet comes from the same verb as “to miss a target.” Avera, like the English word “transgression,” means “to cross a boundary, to enter forbidden territory, to be in a place once should not be.”
Two Concepts of Teshuvah (Nitzavim, Covenant & Conversation)