The idiom heads up is used as a warning to help others become more aware of something.
The Origin Of ‘Heads Up’
The origin of this phrase is unclear. The earliest I could find it in print is from the early 20th century. For example, the quote below is from the Daily Express newspaper, 1910, and it says:
“Attention! Eyes Front! Heads Up! Listen! You’ll thank us for calling your attention to these 50×163 foot lots. Every improvement: not some.”
In addition, this phrase was a term used in sports. It is defined in the following example that comes from The Washington Post newspaper, 1914:
“‘Heads Up,’ a baseball and football term signifying alertness, action…”
So this expression is at least 110 years old.
- Jim’s car window was rolled down and rainy weather was on its way! Hence, his neighbor advised him: “Just a heads up, but I think it’s gonna rain soon, so you might want to roll up your car door’s window.”