Is none of someone's business - Idioms by The Free Dictionary
be none of (one's) business (redirected from is none of someone's business)
be none of (one's) business
To not be something that one needs to know or worry about; to be something private. It's really none of his business what I do with the money I earn.
be none of somebody’s ˈbusiness,
be no business of somebody’s (informal) a person has no right to know something: ‘How much do you earn?’ ‘That’s none of your business.’ ♢ It’s no business of yours who I go out with.