Crazy, insane.
A device used to store hats upon, consisting of a vertical pole with a sturdy base to prevent toppling, and an array of pegs to hold the hats.
Fickle.
Readily decomposable.
Not stable.
Radioactive, especially with a short half-life.
Unpredictable.
Having a strong tendency to change.
Fluctuating; not constant.
To release (an animal) from a stable.