to show that somebody/something is right or reasonable

to give an explanation or excuse for something or for doing something

The senator made an attempt to justify his actions.

The Prime Minister has been asked to justify the decision to Parliament.

You don't need to justify yourself to me.

He sought to justify taking these measures by citing the threat of a terrorist attack.

The press release was intended to justify them sacking her.

to arrange lines of printed text so that one or both edges are straight

LEARNit Dictionary