transitive verb
1. to demonstrate (something) to be true or valid.
You’ll need solid evidence to justify your claim.
2. to give reasonable grounds for or attest to the rightness of; warrant.
He justified his decision to stay, saying it was best for his wife and children.
He justified eating a big dinner by reminding himself that he hadn’t had lunch.
I can’t justify your spending so much money on clothes.
She tried to justify her betrayal of her friend, but in the end she could not rid herself of guilt.