unstable

instable

Risque de bouger, tomber, céder ou changer brusquement faute de solidité ou de sécurité.

En anglais simple : Likely to move, fall, fail, or change suddenly because it is not firm or secure.

• This chair is unstable.
• The house stood on unstable ground.
• Engineers warned that the damaged bridge was unstable.

Synonymes : unsteady, insecure

Contraires : stable, steady

Expressions courantes : unstable ground, unstable structure, unstable ladder

instable, variable

Change souvent ou brusquement au lieu de rester pareil.

En anglais simple : Changing often or suddenly rather than staying the same.

• Fuel prices are unstable.
• The country remained politically unstable for years.
• Unstable weather made it difficult to plan the trip.

Synonymes : changeable, volatile

Contraires : stable, constant

Expressions courantes : unstable prices, politically unstable, unstable economy

instable

Se décompose facilement ou se transforme en d’autres substances par réaction chimique.

En anglais simple : Likely to break down chemically or change into other substances easily.

• The compound is chemically unstable.
• Heat can make this substance unstable.
• Unstable molecules may break apart during storage.

Contraires : stable

Expressions courantes : chemically unstable, unstable compound, unstable molecule