1. sth that is not of sb's concern, something considered private
that is none of my/your business
If someone tells you that something is 'none of your business' it means it doesn't concern you for the information you're looking for is private. This is a very direct informal way of telling someone to stop asking about something or avoiding answering something. This phrase could be insulting if used wrongly. "What way did you vote in the referendum? - That's none of your business." "Can you tell me how much you make in a year? - That's really none of your business."