heads up

head up

1. Literally, to orient someone or something in the proper direction. In this usage, a noun or pronoun can be used between "head" and "up." Head up the animals, will you? We need to get them back into the barn.
2. To lead some group or delegation. Who will head up the committee for this initiative?
See also: head, up

heads up

1. An interjection used as a warning for imminent danger or something that one needs to be aware of. "Heads up!" he shouted as the brick fell off the edge of the building. Heads up, the boss is looking for you and she looks angry!
2. noun A preliminary notice, especially of future difficulty, trouble, or danger; a warning. Often hyphenated. Make sure everyone gets the heads-up about the inspection tomorrow morning. We don't want anyone coming in unprepared. Hey, just a heads-up—the boss is in a foul mood, so don't do anything to attract attention to yourself! Just give me a heads-up if you need a ride.
See also: head, up
Farlex Dictionary of Idioms.

Heads up!

Raise your head and look around you carefully for information or something that you need to see or avoid. Heads up! Watch out for that door! Heads up! There is a car coming.
See also: Head
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

heads up

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]
See also: head, up
The American Heritage® Dictionary of Idioms by Christine Ammer.

Heads up!

exclam. Look out! Heads up! Watch out for the swinging bucket!
See also: Head
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

heads up

Look out; a warning. This slangy interjection dates from the early 1900s. In the later 1900s, the noun heads-up was born with a similar meaning. Thus, “Heads up, John, that branch will hit the power line,” and “Before the book signing Jane gave him a heads-up that some very critical readers would be questioning him.” And James Lee Burke had it in The Glass Rainbow (2010): “‘What’s on your mind?’ ‘Need to give you a heads-up. I got to get some guilt off my conscience as well.’”
See also: head, up
The Dictionary of Clichés by Christine Ammer
See also:
  • head up
  • head into
  • head into (something)
  • knock (someone or something) on the head
  • knock someone or something on the head
  • knock something on the head
  • a head
  • fat
  • nut