lookout

To remain vigilant or carefully watchful (for something or someone). They should be arriving any minute, so keep a sharp lookout. Keep a sharp lookout for a Christmas present we could give your mother. Keep a sharp lookout for the health inspector, we heard he'll be doing a surprise inspection someday soon.

Watching for something or someone. Be on the lookout for my e-mail! It will have all the instructions you need for the project. A: "What are you guys doing?" B: "We're on the lookout for mom's car, so we can tell dad to stop working on her surprise gift when she gets here."

to gaze outward from inside something. (Of is usually retained before pronouns.) Look out of the window and see if it is raining. I looked out of the door to see what the weather was like.

watchful for someone or something. Be on the lookout for signs of a storm. I'm on the lookout for John, who is due here any minute.

to watch what is happening and be careful But when the ice suddenly breaks, look out.

to watch carefully for someone or something to appear Keep an eye out for signposts for Yosemite.

Also, keep a sharp lookout for. Be watchful for something or someone, as in Keep an eye out for the potholes in the road, or They told him to keep a sharp lookout for the police. The first expression, sometimes amplified to keep a sharp eye out for, dates from the late 1800s, the variant from the mid-1700s. Also see have one's eye on, def. 1; keep a weather eye; keep one's eyes open; look out.

Also, watch out. Be careful, be watchful, as in Look out that you don't slip and fall on the ice, or Watch out! There's a car coming. [c. 1600] Also see look out for.

Also, on the watch. Vigilant, alert, as in Be on the lookout for the twins-they're somewhere on this playground, or He was on the watch for her arrival. Both phrases were originally used with upon. Upon the lookout was originally nautical usage, meaning "on duty being watchful" (as for another ship, rocks, or land); it appeared in the mid-1700s, and on replaced upon about a century later. Upon the watch was first recorded in Daniel Defoe's Robinson Crusoe (1719), and on the watch in Jane Austen's Sense and Sensibility (1797).