cleanse, clear self, (be, do) just(-ice, -ify, -ify self), (be turn to) righteous(-ness)

Boyd’s Bible Dictionary:

(judicial righteousness). Through faith in the work of Christ, God places the believer in the state of being permanently righteous before Him (Rom. 5: 16). By the death of Christ, God now offers the free “gift of righteousness” (Rom. 5:17).

Concise Bible Dictionary:

The word δικαίωσις occurs but twice in the New Testament, namely, Romans 4:25 and Romans 5:18. In the former passage it appears to be the equivalent in meaning of faith being imputed to the believer for righteousness, that is, of the believer being accounted righteous. Hence the word “justification” may be said to be the estimation formed in God’s mind of the believer in view of that order of things of which Christ risen is the Head. Such estimation has its expression in Christ Himself, and its consequences are seen in Romans 5.
The question as to how a righteous God can justify a sinner is raised and answered in Romans 3. It is difficult to conceive a subject more momentous for every human being. What is set forth in the gospel at the outset is the vindication of God in righteousness as regards sin by the death of the Lord Jesus Christ, where, in God’s infinite grace to sinners, the question of sin and its judgment has been raised between Himself and the spotless Sin-bearer and settled to His glory. Of Him it is said, “Whom God hath set forth a mercy-seat, through faith in His blood....for the showing forth of His righteousness in the present time, so that He should be just, and justify Him that is of the faith of Jesus.” It is then in the blood of Jesus that God’s judgment of sin is seen, and it is on this righteous basis that He can justify all who believe in Him.
Justification of life (Rom. 5:18) is the righteous bearing into life which is toward all through the one accomplished righteousness of the Lord Jesus Christ even to death, in contrast with the bearing of the one offense of Adam which brought in death and condemnation upon all. What has been effected by the one Man, Jesus Christ, abounds in the scope of it, over all that has been brought in by the one man Adam. In the death of Christ there is seen the complete judgment and removal out of the sight of God both of the sins and of the man who sinned, believers having, through the Lord Jesus Christ raised from the dead, a new Head, in whom they live for God.
There is another aspect of justification referred to in the Epistle of James (James 2), where it is entirely a question of what appears before men. “Show me thy faith without thy works, and I will show thee my faith by my works.”

Strong’s Dictionary of Hebrew Words:

Transliteration:
tsadaq
Phonic:
tsaw-dak’
Meaning:
a primitive root; to be (causatively, make) right (in a moral or forensic sense)
KJV Usage:
cleanse, clear self, (be, do) just(-ice, -ify, -ify self), (be turn to) righteous(-ness)