- When the weather changes from freezing to hot to freezing rapidly and without reason, this is an example of a time when it is unstable.
- When a person has a bad temper that can explode or flare up with no provocation at all, this is an example of a person who would be described as unstable.
- not fixed, firm, or steady; easily upset or unbalanced
- changeable; variable; fluctuating
- unreliable; fickle
- emotionally or psychologically unsettled
- Chem. tending to decompose or change into other compounds
Origin of unstableMiddle English
- a. Tending strongly to change: unstable weather.b. Not constant; fluctuating: unstable vital signs.
- a. Wavering or fickle: At first, he was unstable in his decisions.b. Showing or marked by erratic or volatile emotions or behavior.
- Not firmly placed; unsteady: an unstable ladder.
- Chemistry a. Decomposing readily.b. Highly or violently reactive.
- Physics a. Decaying with relatively short lifetime. Used of subatomic particles.b. Radioactive.
(comparative more unstable, superlative most unstable)
un- +"Ž stable