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
The coalition has already demonstrated an inability to track weapons in Iraq, a much less complex and unstable battlefield than in Syria.
More importantly, the plot is being built on the unstable foundation of unresolved questions.
But in recent weeks, the Trump-Kushner relationship, the most stable partnership in an often unstable West Wing, is showing unmistakable signs of strain.
This, in combination with modest surface heating, is expected to make the air unstable enough to support sporadic showers and storms.
People too lazy to work on their own primary relationships find temporary thrills with other, new, emotionally unstable and shallow play partners.
The CBO found that the amendment, proposed by Rep. Tom MacArthur, R-N.J, will make the individual insurance markets more unstable in states that take full advantage of its provisions.
Climate change researcher Robert M. DeConto of the University of Massachusetts, Amherst, who worked on a paper that showed just how unstable Antarctica was, shared his thoughts on the climate change science:
Compared to the average hummingbird or fruit fly, such craft are now clumsy and unstable.
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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