Unstable :: Unstable (a.) Not stable; not firm, fixed, or constant; subject to change or overthrow..
Unstack :: Unstack (v. t.) To remove, or take away, from a stack; to remove, as something constituting a stack..
Unstarch :: Unstarch (v. t.) To free from starch; to make limp or pliable.
Unstate :: Unstate (v. t.) To deprive of state or dignity.