Volatile

Unpredictable

Capricious

Erratic

Fickle

Inconstant

Temperamental

Changeable

1 Synonym: Volatile

The stock market is known for its volatile nature, with prices fluctuating rapidly.

His temper was highly volatile, making him difficult to predict.

The chemical reaction proved to be extremely volatile, requiring careful handling.

The political situation in the region remained volatile and uncertain.

2 Synonym: Unpredictable

The weather in the mountains can be highly unpredictable, changing rapidly from sunny to stormy.

Her mood was often unpredictable, making it challenging to gauge how she would react.

The stock market's unpredictable nature can lead to significant financial risks.

The plot of the novel was filled with unpredictable twists and turns that kept readers on edge.

3 Synonym: Capricious

Her capricious decisions made it difficult for her friends to plan anything in advance.

The capricious weather kept changing from sunny to rainy throughout the day.

The boss’s capricious nature led to frequent changes in company policies.

His capricious taste in music meant his playlists were always full of surprises.

4 Synonym: Erratic

His erratic behavior made it hard for colleagues to predict his reactions.

The erratic signal from the satellite disrupted our communication.

The weather has been unusually erratic this season, with sudden temperature swings.

Her erratic driving style caused concern among other road users.