Sin is defined as a cosmic transgression (1 Jn 3:4), complete unrighteousness (1 Jn 5:17), omission of known duty (Js 4:17), not from Bible-based faith (Rom 14:23) and thoughts of abominable foolishness (Prov 24:9; Ps 53ff).
Some people are not aware of their sin. Other people know that they have sinned but never seek the only way to be right with God. If the way to be right with God is sought by mere men not of God, it will only led to further sinfulness of deceit. That is, no one is saved by the world, the flesh, or the devil. God must intervene through His outstretched Spirit and the power of His Word to open hearts in spiritual bestowal of the gift of new faith, new righteousness, new forgiveness, as a new creation (Acts 16:14; Jn 3ff; Tit 3:5; 2 Cor 5:17).