unstable in WordNet English dictionary

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