Vicissitude

[Luis Fok]

Regular change or succession from one thing to
another; alternation; mutual succession; interchange.

[exinilu]

Quite literally change, or chaotic nature. [Vicissitude] would be used to describe the emotional state of mental patients or the chemical properties of [nitro] and [glycerin].

[Kit]

a [natural] [change] visible in [nature] or people

[Gregory]

A change of circumstances or fortune, typically one that is unwelcome or unpleasant.