Tra từ unstable - Từ điển Oxford Advanced Learner 8th

un·stable AW [unstable] BrE [ʌnˈsteɪbl] NAmE [ʌnˈsteɪbl] 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
3. likely to move or fall
•Icebergs are notoriously unstable and are likely to turn over.
4. (technical) (of a substance)not staying in the same chemical or ↑atomic state
•chemically unstable
Opp: ↑stable
see also ↑instability

Synonyms:
mentally ill
insane • neurotic • psychotic • disturbed • unstable
These words all describe sb who is suffering from a mental illness.
mentally ill • suffering from an illness of the mind, especially in a way that affects the way you think and behave
insane • [not usually before noun] (rather formal) suffering from a serious mental illness and unable to live in normal society: ▪ The question is, was the man insane when he committed the crime?
In informal English insane can describe sb who is not suffering from a mental illness, but whose mind does not work normally, especially because they are under pressure. This meaning is used especially in the phrases go insane and drive sb insane.
neurotic • (medical) suffering from or connected with neurosis (= a mental illness in which a person suffers strong feelings of fear and worry): ▪ the treatment of anxiety in neurotic patients
In informal English neurotic is also used to describe sb who is not suffering from a mental illness, but is not behaving in a calm way because they are worried about sth: ▪ She became neurotic about keeping the house clean.
psychotic • (medical) suffering from or connected with psychosis (= a serious mental illness in which thought and emotions lose connection with external reality). In informal English psychotic is sometimes used to describe anyone suffering from a mental illness, but in correct medical usage it only describes people who have difficulty relating to external reality. It contrasts with neurotic which describes people who are less seriously mentally ill and are still able to distinguish what is real from what is not.
disturbed • mentally ill, especially because of very unhappy or shocking experiences: ▪ He works with emotionally disturbed children.
unstable • having emotions and behaviour that are likely to change suddenly and unexpectedly
neurotic/psychotic/disturbed/unstable behaviour
neurotic/psychotic illnesses/disorders/symptoms/patients
seriously mentally ill/neurotic/psychotic/disturbed
emotionally/mentally disturbed/unstable

Example Bank:
•The building trade is notoriously unstable.
•The building was beginning to get unstable.
•The wall was dangerously unstable.
•a politically unstable region
•vulnerable, emotionally unstable individuals
•He's highly unstable, and liable to sudden fits of rage.
•This would leave us with either a very unstable currency or very unstable interest rates.
•We are talking about how these people cope in a politically and economically unstable environment.
•emotionally unstable patients