heads up

heads up idiom
A warning to watch out for potential danger, as in Heads up, that tree is coming down now! The expression is generally in the form of an interjection. [c. 1940]

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Comments
Improve this definition.
Do you have more to add? Share your linguistic knowledge or observation.
/Register to save your comments.