C2 noun /ˈɒnwiː/ or /ˈɑːnwiː/
ennui
тоска
Meaning
A feeling of boredom, listlessness, or dissatisfaction arising from lack of excitement.
Example
After weeks of doing nothing, he sank into a deep sense of ennui.
После недель без дела, он погрузился в глубокую тоску.