Main entry: unstable
Definition: lacking stability or fixity or firmness
Usage: unstable political conditions; the tower proved to be unstable in the high wind; an unstable world economy
Antonyms: stable
Definition: resistant to change of position or condition
Antonyms: nonexplosive
Definition: not explosive
Antonyms: tough
Definition: resistant to cutting or chewing
Definition: physically toughened
Antonyms: tough
Definition: not given to gentleness or sentimentality
Antonyms: nonvolatile, nonvolatilisable, nonvolatilizable
Definition: not volatilizing readily
Main entry: fluid, unstable
Definition: subject to change; variable
Usage: a fluid situation fraught with uncertainty; everything was unstable following the coup
Antonyms: unchangeable
Definition: not changeable or subject to change
Main entry: unstable, precarious
Definition: affording no ease or reassurance
Usage: a precarious truce
Antonyms: easy
Definition: free from worry or anxiety
Main entry: unstable
Definition: highly or violently reactive
Usage: sensitive and highly unstable compounds
Antonyms: unreactive
Definition: (chemistry) not reacting chemically
Main entry: unstable
Definition: disposed to psychological variability
Usage: his rather unstable religious convictions
Antonyms: resolute
Definition: firm in purpose or belief; characterized by firmness and determination
Main entry: mentally ill, unsound, unstable
Definition: suffering from severe mental illness
Usage: of unsound mind
Antonyms: sane
Definition: mentally healthy; free from mental disorder