Other forms: lookouts
A lookout is somebody watching for danger, and the place they watch from. Keep a lookout, post a lookout, the lookout spotted it.
The Titanic's lookouts had no binoculars, which is one of the small facts that shadow the whole story. On the lookout for means actively searching. That's your lookout is British for that is your problem, from an older sense meaning your concern.
1nounlookoutSomebody watching for danger, or the place they watch from.
“One of the boys stood at the corner as a lookout while the others climbed the wall.”
lookout is a watcher, or a post.
Deverbal from look out.
Etymology from Wiktionary, CC BY-SA