WHAT IS THE MEANING OF RIGHTEOUSNESS?

The Biblical expression of the word "righteousness" is rendered as "justification." The fully explanation of the matter is found in the Christian Greek Scriptures, basically carrying the idea of "absolving" or "clearing" of any charge, holding as "guiltless," and hence "acquitting," or pronouncing and treating as righteous.
Paul, the apostle, speaks of God as being "proved righteous" in His Words" and winning when being judged by detractors. Paul stated that the person who dies is "acquitted from his sin,"having paid the penalty of death. Paul, in 2 Corinthians, chapter 10, shows to those who look at things according to their face value, the need to make a proper evaluation of matters, to look at both sides of the ledger, as it is. At the same time, Paul is concerned that 'no one should put to his credit" more than was correct as regard on his ministry. (2 Corinthians 12).
Jesus said that "wisdom is proved righteous by its works" and that, when rendered an account on Judgment Day, men would be "declared righteous" or "condemned by their words."
Jesus also said that the humble tax collector "who prayed repentantly"in the temple "went down"to his home "proved more righteous" than the boastful Pharisee praying at the same time.
Righteousness also refers to "an act of God" whereby one is accounted "guiltless,"  and in declaring a person "perfect in integrity,"and "judged worthy of the right of life."
The first man was perfect, righteous, and considered a son of God, by virtue of God's creation of him and was declared "very good" by His Creator. But man failed to maintain integrity before God and lost righteousness for himself and for his future offspring.
From among his descendants there came "men of faith" who "walked with the True God,"such as Noah, Enoch, and Job.
Of Abraham, it is stated that he exercised "faith in God" and it was "counted to him as righteousness."
The Greek understanding of the word "count" was used regularly in ancient times for numerical calculations such as in accounting, being used when referring both to something that was entered on the  "debit side" of an account and also to something enetred on the credit side thereof.
In the Scriptures, in general, it is used to mean "reckon (group, class, or type), credit, count, rate, taking into account, esteem, and appraise,"
In 1 Corinthians, chapter 13, says that "Love does not keep 'account' of the injury."David, the Psalmist, is quoted in Romans, chapter 4, saying that "Happy is the man whose 'sin' God will by no means 'take into account.'"
Rahab of Jericho "manifested her faith by her works,"and so was "declared righteous,"and her life being spared when the city of Jericho was destroyed.