none of business

none of (one's) business

Something that is of no concern to another. It's really none of his business what I do with the money I earn.
See also: business, none, of
Farlex Dictionary of Idioms.

none of someone's business

not of someone's concern. (A gentle rebuke.) Q: When are you going to leave for home? A: None of your business. How I managed to afford all this is none of your business.
See also: business, none, of
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • none of (one's) business
  • none of one's business
  • none of your business!
  • like nobody’s business
  • like nobody's business
  • How's business?
  • business woman
  • go about (one's) business
  • go about your business
  • open for business