dikaioō — to declare righteous, justify

Righteousness in the Bible is being in right standing — with God, with others, and with the moral order God has built into the world. It is both a gift declared and a life lived. The Old Testament tsedaqah and the New Testament dikaiosune carry both meanings.

To be justified is to be declared righteous before God's tribunal. It is a courtroom verdict, not a slow improvement — given freely on the basis of Christ's righteousness, received by faith.