vicissitude

/vɪˈsɪs.ɪˌt(j)uːd/

Etymology

From Middle French vicissitude, from Latin vicissitūdō (“change”), from vicissim (“on the other hand, in turn”), from vicis (“change, vicissitude”), whence Portuguese vez and French fois (“time (as in "next time"), occurrence”).

vicissitude means regular change or succession from one thing to another, or one part of a cycle to the next; alternation; mutual succession; interchange; variability. Lexicurio rates it Sui generis — a strength score of 85 out of 100.

Why this word is great

VICISSITUDE — [Noun] A change or variation, especially one in the course of life or fortune, often of an unpredictable or challenging nature. From Middle French vicissitude, from Latin vicissitŭdō ("change"), from vicissim ("on the other hand, in turn"), from vicis ("change, turn"). Unlike "fluctuation," which suggests a gentle, often quantitative back-and-forth, or "transition," which implies a planned or natural passage, vicissitude speaks to the inherent, often sharp undulation of fate. It is the sudden frost that blights an orchard in bloom, the friend who becomes a stranger overnight, the stranger at a party who becomes your spouse—the relentless, turning wheel that grinds mere happenstance into the substance of a life, a terrain of upheavals whose only constant is the certainty of its next installment.

noun

Regular change or succession from one thing to another, or one part of a cycle to the next; alternation; mutual succession; interchange; variability.
A change, especially in one's life or fortunes.“And God made.. the Stars, and set them in the firmament of Heaven to illuminate the Earth, and rule the day in their vicissitude...”