Thayer's Greek Lexicon

 1. righteous, observing divine laws
  1) in a wide sense, upright, righteous, virtuous, keeping the
commands of God
1a1. of those who seem to themselves to be righteous, who pride
themselves to be righteous, who pride themselves in their
virtues, whether real or imagined
1a2. innocent, faultless, guiltless
1a3. used of him whose way of thinking, feeling, and acting is
wholly conformed to the will of God, and who therefore
needs no rectification in the heart or life
1a  1) only Christ truly
1a4. approved of or acceptable of God
  2) in a narrower sense, rendering to each his due and that in a
judicial sense, passing just judgment on others, whether
expressed in words or shown by the manner of dealing with them