Thayer's Greek Lexicon

 1. in a broad sense: state of him who is as he ought to be,
righteousness, the condition acceptable to God
  1) the doctrine concerning the way in which man may attain a
state approved of God
  2) integrity, virtue, purity of life, rightness, correctness
of thinking feeling, and acting
2. in a narrower sense, justice or the virtue which gives each his due