unstable

US /ʌnˈsteɪ.bəl/
UK /ʌnˈsteɪ.bəl/
"unstable" picture
1.

不稳定的, 不牢固的

likely to change or give way; not stable

:
The old bridge is structurally unstable.
这座旧桥结构不稳定
The political situation in the region remains highly unstable.
该地区的政治局势仍然高度不稳定
2.

情绪不稳定的, 反复无常的

prone to erratic or unpredictable changes of mood or behavior

:
He's been very unstable since the divorce.
离婚后他一直很不稳定
Her emotions are quite unstable, swinging from joy to sadness quickly.
她的情绪相当不稳定,很快从快乐转为悲伤。