unstable

• Qualifie quelque chose qui n'est pas stable, solide ou fiable ; susceptible de changer ou de tomber en panne.

Describes something that is not stable, firm, or steady; likely to change or fail.

1. Lacking stability or firmnessB1formal

   Not firmly fixed; likely to move, change, or fail.

   instable

   • The ladder felt unstable and I was afraid to climb it.
   • The political situation in the region remains unstable.
   • The patient's condition is still unstable after the surgery.

   Synonymesinsecureprecariousricketyrockyshakytotteryunsoundunsteadywobbly

   Antonymesfirmfixedsecuresolidstablesteady

2. Highly reactiveB2formalscientific

   Describing a chemical substance that is likely to react or decompose quickly.

   instable (chimie)

   • This compound is highly unstable and must be stored carefully.
   • Unstable elements can cause dangerous reactions if mishandled.
   • The lab technician handled the unstable chemical with extreme caution.

   Synonymeslabilereactivevolatile

   Antonymesinertstable

3. Not reassuringB2formal

   Causing worry or unease; not providing comfort or safety.

   qui inquiète

   • The economy is in an unstable state, causing anxiety among investors.
   • His unstable behavior at the meeting made everyone uncomfortable.
   • The building's unstable foundation gave little reassurance to the residents.

   Antonymescalmingreassuringsecurestablesteady

4. Severe mental illnessC1formalmedical

   Suffering from a serious mental health condition that affects behavior and thinking.

   Instable mental

   • The patient was diagnosed as mentally unstable and required constant care.
   • He was deemed unstable after the psychological evaluation.
   • The court ordered treatment for the unstable individual.

   Synonymesderangedinsanemadpsychoticunbalancedunhinged

5. Prone to psychological variabilityC1formal

   Tending to have unpredictable or changeable moods and emotions.

   instable émotionnellement

   • She is emotionally unstable, often swinging from joy to sadness quickly.
   • His unstable temperament made it hard to maintain relationships.
   • The character in the novel is portrayed as psychologically unstable.

   Synonymescapriciouschangeableerraticmercurialmoodytemperamentalunpredictablevolatile

   Antonymesbalancedcomposedequablelevelheadedstablesteady

6. Subject to changeB2formal

   Likely to change frequently; not constant or steady.

   instable

   • The weather in spring is often unstable, with sudden rain and sunshine.
   • The company's profits have been unstable over the past few years.
   • Her mood is unstable, shifting from cheerful to irritable without warning.

   Synonymeschangeableficklefluctuatingfluidinconstantmercurialmutableunsteadyvariablevolatile

   Antonymesconsistentconstantfixedinvariablestablesteadyunchanging