Unsleeping, watchful, vigilant. Also figurative.

That watches; observant, vigilant, unsleeping.

That remains awake; that keeps watch; figurative that continues on the alert, vigilant, watchful.

Wakeful, watchful.

Of persons: Watchful on all sides, attentive to everything, cautious, heedful of all circumstances that may affect action or decision.

Wakeful and watchful; keeping steadily on the alert; attentively or closely observant.

Listening attentively; attentive, alert.

Watchful, alert, vigilant.

Vigilant.

Habitually keeping awake; figurative keeping on the alert, vigilant, watchful.

Observant, vigilant; (later also more generally) careful. Obsolete (English regional (northern) in later use).

Of a person, animal, etc.: having open eyes; awake; vigilant. Also in extended use.

extremely watchful or sharp-sighted.

Of persons or animals, their dispositions or faculties: Engaged in or accustomed to watching or close observation; vigilant.

Originally Military. Engaged in close observation of a situation or event, one's surroundings, etc… In predicative use.

figurative. In activity; vigilant, watchful, on the alert.

Const. of. Obsolete. rare.

Watchful; careful.