an experience that is very frightening and unpleasant, or very difficult to deal with
کابوس, رویای وحشتناک, خواب ترسناک
The trip turned into a nightmare when they both got sick.
(informal)Nobody knows what's going on—it's a nightmare!
(informal)Filling in all those forms was a nightmare.
Losing a child is most people's worst nightmare.
If it goes ahead, it will be the nightmare scenario.
Travel in the city was becoming a logistical nightmare.
What a nightmare for you!