Wavering; undecided.
Easily shaken; tottering; unsound.
Shaking or trembling.
Full of shakes or cracks; cracked.
Nervous, anxious.
Fluctuating; not constant.
Readily decomposable.
Not stable.
Radioactive, especially with a short half-life.
Unpredictable.
Fickle.
Having a strong tendency to change.
To release (an animal) from a stable.