Sin

God is holy and perfect. Hence His standard for living is holiness and perfection. It is impossible for us to be perfect and everyone knows it. Anyone who is honest with themselves admits to not being perfect. This imperfection we all experience on a daily basis is what the Bible is talking about when it refers to "sin".

The word "sin" actually comes from a Greek word that was used as a measurement in archery. Essentially people would measure the distance from where the arrow hit the target to the bulls-eye in sins. Imperfection...get it? However, author Randy Newman in his book Questioning Evangelism states that the archery analogy is an incomplete one (and I agree with him). He gave me permission to quote him:


“Sin is simply missing the mark,” they say. “The same Greek word for sin is used as an archery term, so we’re all just ‘target-missers.’”
Well, the same Greek word might be used, but the two concepts couldn’t be further apart. When the Bible describes the nature of our rebellion against God, it paints an uglier picture than our simply missing a bull’s eye (see Rom. 3:10–18). Rather than aiming carefully at God’s target, we turn our backs and shoot arrows everywhere else. Wanting to please ourselves, we ignore the true bull’s eye and set our affections on seductive targets that cannot satisfy, sanctify, or save. We are not primarily target-missers; we are self-centered false-target worshippers.
I wouldn’t suggest saying any of that to a non-Christian, but I would avoid the archery illustration. Following such faulty reasoning, a thoughtful seeker might wonder why God would go to all of the trouble of the Cross simply because we aren’t spiritual Robin Hoods.

That's pretty clear. Thanks Randy! One could be passively indifferent toward God's standard (unaware of or apathetic towards it) or actively rebellious against it (you know and understand it, yet choose to reject it) and be classified as a sinner.

I know this seems bleak, but hang in there. I think the next phrase I'll define is "the Gospel." That's where the good news comes in!