1.
unstable, unsteady, insecure
Not firmly fixed, balanced, or reliable. Used for physical objects, weather, emotions, political situations, employment, and other conditions that may change unpredictably.
天気が不安定だ。
The weather is unstable.
収入が不安定で将来が心配だ。
My income is unstable, and I'm worried about the future.
精神的に不安定な状態が続いていたので、病院を受診した。
I had been in a mentally unstable state for a while, so I went to see a doctor.
不安定 is the negation of 安定 (stable, steady).
COMMON COLLOCATIONS:
- 精神的に不安定 (mentally unstable)
- 不安定な天気 (unstable weather)
- 不安定な雇用 (insecure employment)
- 政情不安定 (political instability)
- 不安定な足場 (unsteady footing)
The opposite is 安定 (stable, steady).