Unstable
Part of speech: adjective
Definition: Having a strong tendency to change Fluctuating; not constant fickle unpredictable Readily decompasable Radioactive, especially with a short half-life
Example sentence: I think some people are mentally unstable, and I don't think I should be around them.
Reactive
Part of speech: adjective
Definition: that reacts or responds to a stimulusthat readily takes part in reactionsCharacterized by induction rather than capacitance.Reacting to the past rather than anticipating the future, not predictive.
Example sentence: The luxury market and its consumer are very flexible and reactive.