unstable

1. ADJ You can describe something as unstable if it is likely to change suddenly, especially if this creates difficulty or danger. 不稳定的

The situation is unstable and potentially dangerous. 情况不稳定，可能有危险。

2. ADJ Unstable objects are likely to move or fall. 不牢固的

Both clay and sandstone are unstable rock formations. 黏土和砂岩都是不坚固的岩石构造。

3. ADJ If people are unstable, their emotions and behaviour keep changing because their minds are disturbed or upset. 多变的 (情绪或行为)

He was emotionally unstable. 他情绪多变。