COMMON If something, especially a bad thing, happens under your nose, it happens in your presence or very near to you, and you either do not notice it or cannot do anything to stop it. I became convinced that something sinister was taking place right under my nose. Then suddenly I knew what had been going on here all along, right under our noses. Note: You can also say that someone takes something from under your nose, meaning that they steal it in your presence or very near to you, and you either do not notice it or cannot do anything to stop it. The prisoners stole it from under the noses of two red-faced police officers.