1. become involved or interfere in something that does not concern you
don't stick your nose into my business
If you 'stick your nose into something' or 'poke your nose into' something it means to become involved in something that is not your business or your responsibility. Usually when you 'stick your nose into something' you are behaving in an intrusive way or being nosey. Sometimes people 'stick their noses into' things in order to find out information or to discover something that they don't know. This is a casual idiomatic expression with a negative connotation.