unstable

不安定な

しっかりしておらず、動いたり倒れたり急に変わったりしやすい。

やさしい英語で： 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.

類義語： unsteady, insecure

反対語： stable, steady

よく使う表現： unstable ground, unstable structure, unstable ladder

不安定な、変動する

同じ状態を保たず、頻繁に、または急に変わる。

やさしい英語で： 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.

類義語： changeable, volatile

反対語： stable, constant

よく使う表現： unstable prices, politically unstable, unstable economy

不安定な

化学的に分解したり、別の物質に変わったりしやすい。

やさしい英語で： 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.

反対語： stable

よく使う表現： chemically unstable, unstable compound, unstable molecule