unstable Meaning, Definition & Usage

1. adjective lacking stability or fixity or firmness
   
   • unstable political conditions
   • the tower proved to be unstable in the high wind
   • an unstable world economy
2. adjective satellite highly or violently reactive
   
   • sensitive and highly unstable compounds
3. adjective satellite affording no ease or reassurance
   precarious.
   
   • a precarious truce
4. adjective satellite suffering from severe mental illness
   unsound; mentally ill.
   
   • of unsound mind
5. adjective satellite disposed to psychological variability
   
   • his rather unstable religious convictions
6. adjective satellite subject to change; variable
   fluid.
   
   • a fluid situation fraught with uncertainty
   • everything was unstable following the coup

WordNet