unstable

ailahtelevainen

epävakaa

sairas Having a strong tendency to change.
(quote-magazine)
fluctuating Fluctuating; not constant.
fickle Fickle.
unpredictable Unpredictable.
puhekieltä Readily decompose decomposable.
puhekieltä radioactive Radioactive, especially with a short half-life.
puhekieltä To release (an animal) from a stable.
1992, Elizabeth Darracott Wheeler, Sir John Dodderidge, Celebrated Barrister of Britain, 1555-1628

When the last tune of music floated from the fleet, he unstabled his quarter horse and headed for the coastal road leading west and north on his circuit.