Lookout
/ˈlʊkaʊt/
noun
A vantage point with a view of the surrounding area.
A session of watching for an approaching enemy, police, etc.
“We kept a lookout all night, but nobody came.”
A person on watch for approaching enemy, police, danger, etc.
“The raid failed when the lookout noticed the enemy group.”
Synonyms: lookout man, sentry, surveillance, vigil, watch