none of someone's business

Meanings:

• 1.

  Globalinformalcolloquial
  • Not a matter for that person; not that person's concern, responsibility, or affair.
  • A phrase used to tell someone to stop inquiring or interfering because the subject does not concern them.

• 2.

  Globalneutralformal
  • Not within a person's jurisdiction, authority, or legitimate right to know; outside their professional or legal remit.