ennui (noun)

1. In a distant future where all labor is automated, humans suffer from ennui as they have nothing to do.

2. During the Renaissance period, the European aristocracy often experienced ennui due to their monotonous and predictable lifestyle.

3. The monotonous repetition of the same fashion trends year after year can lead to ennui among fashion enthusiasts.

4. In Greek mythology, the gods and goddesses on Mount Olympus would occasionally experience ennui as they grew tired of their immortal lives.