Definition of unstable in English:

unstable

adjectiveunstablest, unstabler

  • 1Likely to give way; not stable.

    ‘the unstable cliff tops’
    • ‘The slopes and cliffs reflect a highly unstable and dynamic landscape.’
    • ‘Officers said overloaded caravans were unstable and difficult to control.’
    • ‘Yet this one is so poorly made that the mast at sea would have twisted, making the ship unstable and difficult to control.’
    • ‘The choice of operation depends on how large the protrusion is, how many nerves are involved and how stable or unstable the spine is.’
    • ‘The unstable ground underneath his feet suddenly gave way, and he fell into a deep sinkhole.’
    • ‘Luckily, it caught a jar full of pencils, already unstable and perched precariously on the edge of the desk.’
    • ‘However it was found to be geologically unstable and would likely blow itself to ashes in about six cycles.’
    • ‘Following this extended period of stability the slope, whilst still grazed grassland, suddenly became unstable.’
    • ‘As you might be aware, Tokyo is built on some slightly unstable land, prone to all manner of natural disasters, especially earthquakes.’
    • ‘Conditions in the mine were so unstable that rescue workers could not enter the shaft to retrieve the bodies for almost 24 hours.’
    • ‘Unfortunately, there are not enough of the biggest bricks which means that the cross section of the tower is only one lego element wide at the top and very unstable.’
    • ‘Death of the whole tree will not be immediate, but reduced root development will make the larger trees unstable and therefore prone to wind-blow.’
    • ‘The last remaining member of the Hail family rose from her seat, balancing precariously on unstable legs.’
    • ‘Even when it was discovered that the land was unstable and prone to landslide, the squatters remained.’
    • ‘Construction of drilled piles in unstable soil is difficult because soil can contaminate the pile.’
    • ‘The thief and his pursuers were uncertain on their feet while they tried to traverse the unstable landscape.’
    • ‘Just inside the entrance many large rocks had fallen and lots of loose rubble, indicating that the entrance was unstable and prone to rock falls.’
    • ‘Due to natural erosion the cliff was inherently unstable, and there had been at least two landslips on the authority's land.’
    • ‘Such steep slopes are unstable and prone to slumping, so deltas often collapse.’
    • ‘Calm funded the project to avoid safety worries over unstable cliff faces and walking trails.’
    unsteady, rocky, wobbly, wobbling, rickety, shaky, tottery, tottering, teetering, doddery, unsafe, unbalanced, unreliable, insecure, not secure, unfastened, unsecured, movable, precarious
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    1. 1.1 Likely to change or fail; not firmly established.
      ‘an unstable government’
      • ‘Political fragmentation has been a problem, and coalitions between parties have been unstable.’
      • ‘The conditions of patients admitted to the trauma room are usually unstable and critical.’
      • ‘However, base rates are inherently ambiguous, unreliable and unstable.’
      • ‘Without citizens who possess these qualities, democracies become difficult to govern, even unstable.’
      • ‘Other staff contend with phone lines that don't work, uncertain supply lines, and a power system that is unstable at the best of times.’
      • ‘Today they read as uncanny reflections of our own unstable, uncertain age.’
      • ‘Wahid, at the head of an unstable multi-party coalition, is attempting a precarious political balancing act.’
      • ‘He said that the difficulties also led to the highly unstable domestic prices and deterioration in living conditions.’
      • ‘Nuclear power is like that - unpredictable, unstable and ultimately as dangerous as it gets.’
      • ‘Throughout the 1990s, politics were extremely unstable, with frequent changes of government.’
      • ‘It is a very unstable region, where changes can occur brutally.’
      • ‘The problem is from the ground up it's a very unstable technology in terms of specifications.’
      • ‘Experts have said that the unstable exchange rate created difficulties in reaching debt restructuring agreements.’
      • ‘The economy is unstable and unpredictable, and people have to adapt to many changes to survive.’
      • ‘Unstable voltage lines mean an unstable system and this is the last thing people want.’
      • ‘The subjectivity of decisions made by these people makes global financial markets extremely unstable.’
      • ‘At the same time, the incomes - and jobs - they do have are far more unstable than they were a few decades ago.’
      • ‘However, you could be forgiven for thinking that the future for competitive operators looks highly uncertain and unstable.’
      • ‘They are the future of our country and if we allow a bad situation get worse, then we are setting the country on a road to an unstable and uncertain future.’
      • ‘It is not necessary to point out that when the economy is on track, the unstable labor market problem resolves itself.’
      changeable, volatile, variable, unsettled, fluctuating, inconstant, inconsistent, irregular, fitful, unpredictable, unreliable, fickle, capricious, mercurial, erratic, uncertain, wavering
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    2. 1.2 Prone to psychiatric problems or sudden changes of mood.
      ‘he was mentally unstable’
      • ‘The men became uncontrollable, emotionally unstable and dangerously paranoid.’
      • ‘We are expecting that the western media will portray him a crazy or an unstable person - he was the opposite.’
      • ‘So I didn't want to open the door to the mental hospital, but I was forced to because of her unstable state.’
      • ‘Defence counsel argued that Cowle was mentally unstable, but the prosecution said he was not insane in the legal sense.’
      • ‘Police say Bazell, who had a ticket for a domestic Delta flight, appeared mentally unstable.’
      • ‘Both emotionally stable and unstable students can benefit from a better understanding of psychology.’
      • ‘If Khouri is as mentally unstable as the article implies then that's a bit harsh, don't you reckon?’
      • ‘It appears that he had a lively genius, but was unstable, erratic, and weak.’
      • ‘He is accusing this woman of mentally unstable demeanour when, in fact, he seems to be the most qualified for such a label.’
      • ‘When a suspect is mentally unstable, officers are trained to back off and call in a crisis intervention team.’
      • ‘Leading up to her death, the weeks before her death, many people seemed to think she was mentally unstable.’
      • ‘The diagnosis is that of an emotionally unstable borderline personality disorder.’
      • ‘A hitman is assigned to kidnap the mentally unstable younger brother of a powerful district attorney.’
      • ‘The ruling affected the treatment of mentally unstable prisoners during trials.’
      • ‘When one is emotionally unstable, alcohol inhibits the ability to confront and solve problems.’
      • ‘From seventeen year old kid with an unstable mother to his rise as a porn god to his fall from grace, Wahlberg is there every step of the way.’
      • ‘Betty is a successful writer who is forced to relive her traumatic childhood when her mentally unstable mother comes to visit.’
      • ‘Ray Liotta plays a reckless and unstable crime boss.’
      • ‘There are, unfortunately, people in the world who are unstable, and who may descend into madness.’
      • ‘Women, in comparison to men, also viewed the defendant as more psychologically unstable.’
      unbalanced, of unsound mind, mentally ill, deranged, demented, crazed, distracted, troubled, disturbed, unhinged, insane, mad, mad as a hatter, mad as a march hare, raving mad, lunatic, out of one's head, out of one's mind, not in one's right mind, neurotic, psychotic
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Pronunciation

unstable

/ʌnˈsteɪb(ə)l/