Webster's Revised Unabridged Dictionary · 1913

Righteous

Righteous , adjective

[Old English rightways, rightwise, Anglo-Saxon rightwīs; riht right + wīs 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