unstable

lacking stability or fixity or firmness

• “unstable political conditions”
• “the tower proved to be unstable in the high wind”
• “an unstable world economy”

highly or violently reactive

• “sensitive and highly unstable compounds”

affording no ease or reassurance

• “a precarious truce”

suffering from severe mental illness

• “of unsound mind”

disposed to psychological variability

• “his rather unstable religious convictions”

subject to change; variable

• “a fluid situation fraught with uncertainty”
• “everything was unstable following the coup”