be none of somebody's business

be none of (one's) business

To not be something that one needs to know or worry about. It's really none of his business what I do with the money I earn.
See also: business, none, of

be none of somebody’s ˈbusiness

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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.
See also: business, none, of