Definition of unstable in English:

unstable

adjective

  • 1Likely to give way; not stable.

    ‘the unstable cliff tops’
    • ‘The thief and his pursuers were uncertain on their feet while they tried to traverse the unstable landscape.’
    • ‘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.’
    • ‘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.’
    • ‘The choice of operation depends on how large the protrusion is, how many nerves are involved and how stable or unstable the spine is.’
    • ‘Following this extended period of stability the slope, whilst still grazed grassland, suddenly became unstable.’
    • ‘Yet this one is so poorly made that the mast at sea would have twisted, making the ship unstable and difficult to control.’
    • ‘The slopes and cliffs reflect a highly unstable and dynamic landscape.’
    • ‘Calm funded the project to avoid safety worries over unstable cliff faces and walking trails.’
    • ‘Officers said overloaded caravans were unstable and difficult to control.’
    • ‘The last remaining member of the Hail family rose from her seat, balancing precariously on unstable legs.’
    • ‘The unstable ground underneath his feet suddenly gave way, and he fell into a deep sinkhole.’
    • ‘Even when it was discovered that the land was unstable and prone to landslide, the squatters remained.’
    • ‘However it was found to be geologically unstable and would likely blow itself to ashes in about six cycles.’
    • ‘Conditions in the mine were so unstable that rescue workers could not enter the shaft to retrieve the bodies for almost 24 hours.’
    • ‘Luckily, it caught a jar full of pencils, already unstable and perched precariously on the edge of the desk.’
    • ‘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.’
    • ‘Construction of drilled piles in unstable soil is difficult because soil can contaminate the pile.’
    • ‘As you might be aware, Tokyo is built on some slightly unstable land, prone to all manner of natural disasters, especially earthquakes.’
    • ‘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.’
    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’
      • ‘Today they read as uncanny reflections of our own unstable, uncertain age.’
      • ‘Unstable voltage lines mean an unstable system and this is the last thing people want.’
      • ‘Throughout the 1990s, politics were extremely unstable, with frequent changes of government.’
      • ‘The economy is unstable and unpredictable, and people have to adapt to many changes to survive.’
      • ‘Political fragmentation has been a problem, and coalitions between parties have been unstable.’
      • ‘The subjectivity of decisions made by these people makes global financial markets extremely unstable.’
      • ‘However, you could be forgiven for thinking that the future for competitive operators looks highly uncertain and unstable.’
      • ‘He said that the difficulties also led to the highly unstable domestic prices and deterioration in living conditions.’
      • ‘It is a very unstable region, where changes can occur brutally.’
      • ‘Nuclear power is like that - unpredictable, unstable and ultimately as dangerous as it gets.’
      • ‘Experts have said that the unstable exchange rate created difficulties in reaching debt restructuring agreements.’
      • ‘The problem is from the ground up it's a very unstable technology in terms of specifications.’
      • ‘However, base rates are inherently ambiguous, unreliable and unstable.’
      • ‘At the same time, the incomes - and jobs - they do have are far more unstable than they were a few decades ago.’
      • ‘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.’
      • ‘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.’
      • ‘It is not necessary to point out that when the economy is on track, the unstable labor market problem resolves itself.’
      • ‘The conditions of patients admitted to the trauma room are usually unstable and critical.’
      • ‘Without citizens who possess these qualities, democracies become difficult to govern, even unstable.’
      • ‘Wahid, at the head of an unstable multi-party coalition, is attempting a precarious political balancing act.’
      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’
      • ‘Betty is a successful writer who is forced to relive her traumatic childhood when her mentally unstable mother comes to visit.’
      • ‘Women, in comparison to men, also viewed the defendant as more psychologically unstable.’
      • ‘Ray Liotta plays a reckless and unstable crime boss.’
      • ‘Defence counsel argued that Cowle was mentally unstable, but the prosecution said he was not insane in the legal sense.’
      • ‘So I didn't want to open the door to the mental hospital, but I was forced to because of her unstable state.’
      • ‘A hitman is assigned to kidnap the mentally unstable younger brother of a powerful district attorney.’
      • ‘He is accusing this woman of mentally unstable demeanour when, in fact, he seems to be the most qualified for such a label.’
      • ‘We are expecting that the western media will portray him a crazy or an unstable person - he was the opposite.’
      • ‘When a suspect is mentally unstable, officers are trained to back off and call in a crisis intervention team.’
      • ‘The men became uncontrollable, emotionally unstable and dangerously paranoid.’
      • ‘The diagnosis is that of an emotionally unstable borderline personality disorder.’
      • ‘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.’
      • ‘Police say Bazell, who had a ticket for a domestic Delta flight, appeared mentally unstable.’
      • ‘There are, unfortunately, people in the world who are unstable, and who may descend into madness.’
      • ‘If Khouri is as mentally unstable as the article implies then that's a bit harsh, don't you reckon?’
      • ‘Both emotionally stable and unstable students can benefit from a better understanding of psychology.’
      • ‘Leading up to her death, the weeks before her death, many people seemed to think she was mentally unstable.’
      • ‘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.’
      • ‘It appears that he had a lively genius, but was unstable, erratic, and weak.’
      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/