It is right doing and right standing; a sincere desire to please God by keeping His laws. Also: Faultless; Having a living trusting relationship with God; Having faith.
Romans 4:3 “For what does the Scripture say? Abraham believed God, and it was credited to him for righteousness.”
Romans 14:17 “for the kingdom of God is not eating and drinking, but righteousness, peace, and joy in the Holy Spirit.”