mind one's own business, to

Fig. to attend only to the things that concern one. Leave me alone, Bill. Mind your own business. I'd be fine if John would mind his own business.

Fig. Stop prying into my affairs. (Not at all polite. The expressions with get and keep can have the literal meanings of removing and keeping removed.) Andy: This is none of your affair. Mind your own business. Sue: I was only trying to help. Bob: How much did you pay in federal taxes last year? Jane: Good grief, Bob! Keep your nose out of my business! Tom: How much did it cost? Sue: Tom! Get your nose out of my business! "Hey!" shrieked Sally, jerking the checkbook out of Sue's grasp. "Get your nose out of my business!"

Keep from meddling, pay attention to one's own affairs, as in If she would only mind her own business, there would be a lot fewer family quarrels. Already described as a wise course by the ancients (Seneca had it as Semper meum negotium ago, "I always mind my own business"), this precept has been repeated in English since about 1600.

To refrain from meddling, to keep to one’s own affairs. The wisdom of this course of action was observed in ancient times by Plato, Seneca, and others, and even found expression in the Bible (1 Thessalonians 4:11, “Do your own business”). In plain English it was expressed from the sixteenth century on. John Clarke used it in Paroemiologia (1639): “Mind your business.” Among many later writers echoing this sentiment was Lewis Carroll, in one of his enjoyable non sequiturs (Alice’s Adventures in Wonderland, 1865), “‘If everybody minded their business,’ the Duchess said in a hoarse growl, ‘the world would go round a great deal faster than it does.’”