Justification (noun)

1. A reason or explanation given to defend or justify a particular course of action or decision.
2. The action or process of making something appear right or reasonable.

Origin:

From old french justification, from latin iustificatio, from iustificare 'to make just'.

Examples:

1. The justification for the policy change was based on a detailed economic analysis.
2. The justification for the war was that it would bring about lasting peace and stability.
3. The justification for the new tax was that it would fund important public services.
4. The justification for the proposed rule change was that it would increase fairness in the game.
5. The justification for the decision was that it was in the best interest of the company and its shareholders.