Often used when someone is nervous about a future event they wish to avoid. As the court date approached, he felt the evil hour looming closer.
Pro Tip 2/3
Procrastination Reference
Used to hint at someone's attempt to delay an inevitable, unpleasant situation. He tried to postpone the evil hour by taking a longer route home.
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Metaphorical Use
Can be applied metaphorically to describe not just a time, but a challenging situation. The evil hour of the company's downsizing was a hot topic among employees.