unstablest

1. Tending strongly to change: unstable weather.

2. Not constant; fluctuating: unstable vital signs.

3. Fickle.

4. Lacking control of one's emotions; marked by unpredictable behavior.

5. Decomposing readily.

6. Highly or violently reactive.

7. Decaying with relatively short lifetime. Used of subatomic particles.

8. Radioactive.

1. Fickle.

2. Lacking control of one's emotions; marked by unpredictable behavior.

3. Decomposing readily.

4. Highly or violently reactive.

5. Decaying with relatively short lifetime. Used of subatomic particles.

6. Radioactive.

Not firmly placed; unsteady: an unstable ladder.

Chemistry

1. Decomposing readily.

2. Highly or violently reactive.

3. Decaying with relatively short lifetime. Used of subatomic particles.

4. Radioactive.

Physics

1. Decaying with relatively short lifetime. Used of subatomic particles.

2. Radioactive.

Liable to undergo spontaneous decay into some other form. For example, the nucleus of uranium 238 atom is unstable and changes by radioactive decay into the nucleus of thorium 234, a lighter element. Many subatomic particles, such as muons and neutrons, are unstable and decay quickly into other particles. See more at decay.

Relating to a chemical compound that readily decomposes or changes into other compounds or into elements.

Relating to an atom or chemical element that is likely to share electrons; reactive.

Characterized by uncertain or inadequate response to treatment and the potential for unfavorable outcome, as the status of a medical condition or disease.