Ennui (noun)

A feeling of listlessness or dissatisfaction resulting from a lack of interest or stimulation.

Origin:

From the french word ennui, which means boredom or weariness.

Examples:

1. He felt a sense of ennui wash over him as he looked out the window.
2. The endless repetition of the same routine led to feelings of ennui.
3. She felt ennui as she sat alone in the empty room.
4. The ennui of the long flight was relieved by a good book.
5. The monotony of the daily commute was beginning to cause ennui.