watchman

As a noun watchman

is one set to watch; a person who keeps guard, especially one who guards a building, or the streets of a city, by night.

As an adjective false is

(label) one of two states of a boolean variable; logic.

As a proper noun monitor

is any of several publications eg the "christian science monitor".

As a noun watchman is

one set to watch; a person who keeps guard, especially one who guards a building, or the streets of a city, by night.

As a noun watchman

is one set to watch; a person who keeps guard, especially one who guards a building, or the streets of a city, by night.

As an adjective undefined is

lacking a definition or value.

As nouns the difference between guardian and watchman

is that guardian is someone who guards, watches over, or protects while watchman is one set to watch; a person who keeps guard, especially one who guards a building, or the streets of a city, by night.

As a proper noun Guardian

is a British daily national newspaper.

As nouns the difference between sentry and watchman

is that sentry is a guard, particularly on duty at the entrance to a military base while watchman is one set to watch; a person who keeps guard, especially one who guards a building, or the streets of a city, by night.

As an adjective vigilant

is watchful, especially for danger or disorder; alert; wary.

As a noun watchman is

one set to watch; a person who keeps guard, especially one who guards a building, or the streets of a city, by night.

As nouns the difference between sentinel and watchman

is that sentinel is a sentry or guard while watchman is one set to watch; a person who keeps guard, especially one who guards a building, or the streets of a city, by night.

As a verb sentinel

is to watch over as a guard.

As nouns the difference between nightguard and watchman

is that nightguard is a guard worn on the teeth to prevent damage from bruxism during sleep while watchman is one set to watch; a person who keeps guard, especially one who guards a building, or the streets of a city, by night.

As nouns the difference between observer and watchman

is that observer is one who makes observations, monitors or takes notice while watchman is one set to watch; a person who keeps guard, especially one who guards a building, or the streets of a city, by night.