Definition of unstable
: not stable : not firm or fixed : not constant: such asa : not steady in action or movement : irregular an unstable pulseb : wavering in purpose or intent : vacillatingc : lacking steadiness : apt to move, sway, or fall an unstable towerd (1) : liable to change or alteration an unstable economy unstable weather (2) : readily changing (as by decomposing) in chemical or physical composition or in biological activitye : characterized by lack of emotional control
unstablyplay \ˌən-ˈstā-b(ə-)lē\ adverb
Examples of unstable in a Sentence
an unstable nuclear reactor core
the minute we put the books down on the unstable desk, the whole stack went crashing to the floor
Recent Examples of unstable from the Web
With unstable air and abundant moisture overhead, and a frontal boundary vacillating over northern Illinois and northwest Indiana, the next two to three days here will be punctuated with periods of showers and thunderstorms.
Things get dangerous if the person is unstable enough.
Born nine months apart in the post-World War II collapse of the British empire, the nations share a democratic tradition and are both located in unstable neighborhoods.
Unstable snow may slide at any time … not just in winter.
That could lead to unstable majorities and a hung parliament in a country where the three main political forces each have about a third of popular consensus.
Pi (July 1) Darren Aronofsky made a splash with his 1998 black-and-white directorial debut about a psychologically unstable math genius who comes to believe that the Torah holds the numerological key to understanding God.
And the special high explosives fabricated by nuclear scientists to compress the plutonium cores in a deliberate detonation also have an unstable molecular structure.
If someone this unstable, this delusional, and this unwell cannot be removed from office, who can?
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'unstable.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
First Known Use of unstable
Synonym Discussion of unstable
UNSTABLE Defined for English Language Learners
Definition of unstable for English Language Learners
: likely to change
: not emotionally or mentally healthy
: not held in a secure position : likely to move or fall
UNSTABLE Defined for Kids
Definition of unstable for Students
: not stable an unstable boat
Medical Definition of unstable
: not stable: asa: characterized by frequent or unpredictable changes a patient in unstable conditionb: readily changing (as by decomposing) in chemical composition or biological activity unstable compoundsc: characterized by lack of emotional control or stability
Seen and Heard
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