lookout

(noun) a person employed to keep watch for some anticipated event. Synonyms: lookout man, sentinel, sentry, watch, spotter, scout, picket.

(noun) an elevated post affording a wide view. Synonyms: observation post.

(noun) a structure commanding a wide view of its surroundings. Synonyms: observation tower, lookout station, observatory.

(noun) the act of looking out. Synonyms: outlook.