You'll have to define what is Sin, why is Sin and how is Sin. If you know of course ..
In order to answer your question in the way you request the answer to be defined, then you will have to look at the Law of Moses. The law was given in order to show the children of Israel what sin is - and it brought death.
But it's much much more than a guidebook of right and wrong - much much more than a penal code. It's much more than breaking the law.
Lawlessness is sin.
but so is Faithlessness (Romans 14:23) as faithlessness - is also DEATH. Living without faith in God is sure death.
If you don't have love then you have nothing - no life in you. (1 Corinthians 13) If you have no life, then you have death - refusing to love - is sin.
You cannot have life apart from God - who is life and who has life in and of Himself. Apart from God, you are dead. You receive this life through Christ, our Lord - without Christ, you are dead.
The wages - the payment or consequence of sin is death. (Romans 6:23)
He gave birth to a new being when we died and were born again in Him. He filled us with His Holy Spirit that we might know what sin is - from our conscience that tells us and rightfully so, when we decide to be the god we serve or when He actually is. When we are self serving, we don't love, when we don't love, do not have God as He IS love (1 John 4:eight (silly smiley faces!) ) - if we do not have God, we do not have LIFE and we are DEAD.
He writes His Law on our hearts, He has given us His Holy Church to guide us, He has given us the Clergy, the Traditions, the Bible, the Divine Liturgy, The Sacraments, The Feasts, The Fasts - all to help us because He loves us so very very much.
But most of all, He gave His only Begotten Son that who so ever believes in Him will not perish (DEATH) and will receive eternal life (LIFE). (John 3:16)
So that we might be forgiven and be reconciled to him when we do decide to taste death. . .walk as a living dead, as it were.
Sin is turning away from God (the only source of TRUE LIFE) in ANY capacity. Sin is choosing to die spiritually and using the worship of ourselves and the world as the excuse to do so.