If someone does not bat an eye when something happens, they do not appear at all shocked or surprised by it. She never batted an eye when I told her I was leaving my job. These people don't bat an eye when they're charged 16 dollars a pound for cheese. Note: You can also say that someone does something without batting an eye. He handed over the money without batting an eye. Note: The usual British expression is not bat an eyelid. Note: Bat is from a French word meaning to beat or flutter and is used of a bird's wings. The idea is that people who do not blink a lot in a given situation appear calm rather than nervous or surprised.