Definitions of unstable:
- adjective: highly or violently reactive
Example: "Sensitive and highly unstable compounds"
- adjective: disposed to psychological variability
Example: "His rather unstable religious convictions"
- adjective: lacking stability or fixity or firmness
Example: "Unstable political conditions"
- adjective: subject to change; variable
Example: "Everything was unstable following the coup"
- adjective: affording no ease or reassurance
- adjective: suffering from severe mental illness