Righteous, a.
Etymology: [OE. rightways, rightwise, AS.rightwis; riht right + wis wise, having wisdom, prudent. See Right, a., Wise, a.]
Doing, or according with, that which is right; yielding to all their due; just; equitable; especially, free from wrong, guilt, or sin; holy; as, a righteous man or act; a righteous retribution. Fearless in his righteous cause. Milton.
Syn. -- Upright; just; godly; holy; uncorrupt; virtuous; honest; equitable; rightful.
Shades of meaning
Fernald has no entry of its own for righteous; he lists it under innocent.
Where he writes about it:
Innocent is a negative word, expressing less than righteous, upright, or virtuous, which imply knowledge of good and evil, with free choice of the good. — from innocent
A little child or a lamb is innocent; a tried and faithful man is righteous, upright, virtuous. — from innocent