volatile
adj.adj. likely to change suddenly and unexpectedly, especially by getting worse. You use this to describe things like prices, weather, or a person's mood when they are unstable.
adj. characterised by rapid and unpredictable change, especially for the worse; in a technical sense, evaporating easily at normal temperatures. Often follows a linking verb or modifies nouns related to markets or temperament.
The stock market has been very volatile this week.
Investors are nervous because the political situation in the region remains highly volatile and could change at any moment.
While the chemical compound is extremely volatile and requires careful storage, the primary concern for the laboratory staff was the researcher's own volatile temper during high-pressure experiments.
From Middle French volatile, from Latin volātilis (“flying; swift; temporary; volatile”), from volō (“to fly”).
Often modified by degree adverbs like 'highly', 'extremely', or 'potentially'.