One can look at sin from two sides...legal and relational.
The legal side is descriptive. It's clear and concise...injunctions are laid out, lists are made, prohibitions are clear and these are found easily within the pages of scripture in both old and new testaments. The Law and the prophets lay out sin and its consequences. From this clarity we see justice, wholeness, purity, perfection, godliness, the ideal, holiness, eternality, glory, light. From these passages we see the image of life as it should be.
The relational side is the spirit behind the law. We see that the clarity of showing sin among us, between us and in us...it has to do with relationships. Sin separates people relationally. There is a side of this that envelops the ideas presented in the NT that have to do with love. Connecting sin to love in phrases like... "That isn't very loving" becomes a relational compass that awakens one to the reality that what they are doing, even if it isn't clearly described somewhere is hurting someone or something and that means you are not loving them. That becomes sin. If one isn't truly walking in faith...for them, and that is the language the bible uses...is sin.
These two sides are one.
Learning to live in love and for the glory of God is a process. It requires learning about the holiness of God and coming to the realization of ones own fallenness. Which brings despair and hope. It involves one despairing of self and seeking the hope given by God, through God and is God...in Jesus Christ. We turn from self and embrace the Son; who becomes for us, salvation, healing, restoration, glorification, life and light. We are born in and through this and from this we grow. And a new life lived in and by the Spirit is entered and we learn to follow the nuances for this relational life.
Sin is present...in both the legal truth and the relational tensions.
Sin crucified the son of God...it's a serious issue. One we must wrestle with, understand, flee, confess, fear, reject and seek freedom from. But it's also a dissonance that should lead us to tune the dial until the music of heaven comes in clearer. An ugly sound within and without...is evidence of a out of tune life. Learning the notes of living...involves this issue of sin. But playing the music is the goal.
Some people who are born legalists or were raised with just light about the demands of holiness and not the remedy and beauty of it....always want to define things. Because they are consumed with being "right" and "good" and love is usually connected to these words to them.
Defining sin is often the evidence of a heart that is still maybe only seeing sin from one side of the coin.
Without the relational side...the legal side is exactingly objective.
With only the relational side of the coin...sin is merely subjective.
We need both sides....but the life of the Spirit...goes beyond these words...as one grows in love.
Soon the definitions becomes irrelevant because the life within, the knowledge of our Father, and the voice of the Holy Spirit and the renewed and reclaimed heart and mind...live in tempo, even with the presence of sin. Sin becomes the fascination and preoccupation of those who have only learned a life of turning from things...instead of the life of turning towards something...or better, Someone.
Turning from sin...is often the tale tell sign of the preoccupation of a Christ-less religion.
Law is a picture of a child reaching out his or her hand...and their Father not reaching back.
Grace is a Father reaching out His hand...and embracing the child's hand.
What picture one sees....will determine the quality and enjoyment of the faith journey.
"Those of us who were brought up as Christians and have lost our faith have retained the sense of sin without the saving belief in redemption. This poisons our thought and so paralyses us in action." -Cyril Connolly
"It takes the same grace of God to save the most respectable person in the world as (it does) the most lawless person in the world" (Martin Lloyd-Jones, Spiritual Depression).
"Sin is whatever obscures the soul."
"He that falls into sin is a man; that grieves at it, is a saint; that boasteth of it, is a devil."
"God has reserved the time of full cleansing of his people, for another world. Christ could cleanse His people presently from all their spots if He desired. Surely, this is the case. But because they are to live in this world for now, Christ sees that it would not benefit them to be wholly cleansed from sin now and live in a sinful world. This world is not worthy of the saints. Even if you consider them with all their infirmities, still, the world is not worthy of them. Yet it is not for the world to have the saints live here without their spots. If the world is offended that Christians have their spots. then let them be offended. Let Christians be stumbling-blocks to them. It is without a doubt, that many saints are stumbling blocks to many souls. The world, they rejoice when they see the sins that are in the saints" -Jeremiah Burroughs Spots of the Godly and of the Wicked
"What then is it in the soul which causes it to take more pleasure in things which it loves when they are found and recovered than if it has always had them" (Augustine Confessions Bk. VIII Pg. 137)
Love, and do what you like.