heads up

¹

interjection

1. (used to call attention to an impending danger or the need for immediate alertness.)

heads-up

²

[ hedz-uhp ]

adjective

1. quick to grasp a situation and take advantage of opportunities; alert; resourceful.

noun

1. a warning in advance:

   sending a heads-up to the Pentagon about possible attacks.

heads up

noun

1. a tip-off or small amount of information given in advance

Word History and Origins

Origin of heads up¹

First recorded in 1940–45

Origin of heads up²

First recorded in 1945–50

Idioms and Phrases

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]