1 general:: Phrase(s): What’s it to you? Inf. Why does it matter to you?; It’s none of your business. (A bit contentious.) • Tom: Where are you going? Jane: What’s it to you? • Mary: Bill’s pants don’t match his shirt. Jane: Does it matter? What’s it to you?
McGrawhill's American Idioms And Phrasal Verbs
2 general:: see WHAT OF IT.
American Heritage Idioms