Righteousness, n.
Etymology: [AS. rihtwisnes.]
1. The quality or state of being righteous; holiness; purity; uprightness; rectitude.
Note: Righteousness, as used in Scripture and theology, in which it chiefly occurs, is nearly equivalent to holiness, comprehending holy principles and affections of heart, and conformity of life to the divine law.
2. A righteous act, or righteous quality. All our righteousnesses are as filthy rags. Isa. lxiv. 6.
3. The act or conduct of one who is righteous. Blessed are they that keep judgment, and he that doeth right at all times. Ps. cvi. 3.
3 more senses
4. (Theol.)
The state of being right with God; justification; the work of Christ, which is the ground justification. There are two kinds of Christian righteousness: the one without us, which we have by imputation; the other in us, which consisteth of faith, hope, and charity, and other Christian virtues. Hooker. Only for the righteousness of Christ imputed to us, and received by faith alone. Westminster Catechism.
Syn. -- Uprightness; holiness; godliness; equity; justice; rightfulness; integryty; honesty; faithfulness.
Shades of meaning
Fernald has no entry of its own for righteousness; he lists it under duty, justice, religion, virtue.
Where he writes about it:
Righteousness is right incarnated in action. — from duty
Integrity, rectitude, right, righteousness and virtue denote conformity of personal conduct to the moral law, and thus necessarily include justice, which is giving others that which is their due. — from justice
Rectitude and righteousness denote conformity to the standard of right, whether in heart or act; righteousness is used especially in the religious sense. — from virtue