Answer: stayalert

AnswerCrossword Clue
STAYALERTWhat a night watchman should do
STAYALERTKeep your eyes open
STAYALERT"Keep your eyes peeled!"
STAYALERT"Keep your eyes open!"
STAYALERT'Keep your guard up!'
STAYALERTProperly maintain a watch
STAYALERTDon't lose focus