Why Bible said we are sinners?

I can’t understand, why Christian always say “sin”, what is sin in Bible?

We don’t know why we are sinners, that’s sin.
We don’t know God well , itself is sin.

Compared with the specific behaviors, the sin’s nature is to live in the wrong relationship without the truth and love form God. As a result, all kind of evil things came out. The Bible clearly tells us the greatest sin is that the people don’t put God in their heart even they know God and don’t thank God.

The original-language Bible words for sin mean ‘to miss a mark or target.’ There are sins of ignorance and sins of omission. we are all sinners.

God created us with much of His fatherly love and care. Believing in us He gave us perfect freedom and the privilege to see Him and live with him every day. He knew we could use this freedom for whatever we want including And He also gave us His Word to tell us the purpose in life as well as something to obey and stay humble. But instead of seeing and accepting this love with faith and returning it, we listen to the voice that says basically: See, God limits you. He wants to keep something from you, that is why you are not allowed to do this or that. If you do it, you will be like God – perfect. You will know good AND evil. And so here we are.

Sin us to abandon God and to reject Him and His love.

In the original Bible, sin means “miss the target”
Our wrong relationship with God, we lost our trust and love to God. all the things become messy.