unstable
adjectiveUK /ʌnˈsteɪ.bəl/
US /ʌnˈsteɪ.bəl/
Not steady and likely to fall or change.
The tower of blocks was unstable and fell down.
RELATED WORDS
OTHER MEANINGS
2. Likely to change suddenly or unpredictably.
The weather has been unstable all week.
3. Emotionally unpredictable or easily upset.
He seemed unstable after the bad news.
4. In chemistry, easily breaking down or reacting.
Some unstable chemicals must be stored carefully.