/ ʌnˈsteɪbl; NAmE / adjective
1.
likely to change suddenly
SYN volatile :
The political situation remains highly unstable.
2.
if people are unstable , their behaviour and emotions change often and suddenly because their minds are upset
➡ note at mentally ill
3.
likely to move or fall
4.
( technical ) ( of a substance ) not staying in the same chemical or atomic state :
chemically unstable
OPP stable
—see also instability