noun
vicissitude
vih-SIS-ih-tood/vɪˈsɪsɪtuːd/
A change in circumstances, especially a difficult or unpredictable one.
The sudden downpour brings a vicissitude that changes the picnic from pleasant to miserable.

Etymology
Latin vicissitudo meant change or alternation, encompassing both regular shifts and turns of fortune. The selected English sense emphasizes a turn in circumstances that is unexpected, especially an unwelcome one.
In context
vicissitude of every human lot
More examples
- Small businesses must adapt to the vicissitudes of the economy.
- Her memoir describes the vicissitudes of raising a family.
- He faces each vicissitude with patience and humor.
Forms
vicissitude · vicissitudes
Similar words
- upheaval
- Emphasizes major disruption rather than changing circumstances generally.
- reversal
- Specifies a turn toward the opposite situation, often worse.
- fluctuation
- Emphasizes repeated rises and falls rather than changes in fortune.