One who watches in the night, especially with evil designs.(noun)
The Century Dictionary (Public Domain)
Use "night-watcher" in a sentence
"The sentinels paced up and down more quickly, to dissipate that feeling of shivering cold which runs through the night-watcher during the first hour of the morn."
"It was doubtless caused by one of those meteors, which the night-watcher may so often observe burning out to waste, in the vacant regions of the atmosphere."
"For Luke had been a constant night-watcher by his masters bed."