(Target effect can only be removed if marked as Movement Impairing Effect or Stun.)
(This skill can be used even if you are in a state that doesn't allow you to cast spells.)
The description implies that you can use this to remove a Movement Impairing Effect or Stun, but I have not found this to be true. You need to anticipate when the mob may hit you with the Debuff, then use this first. It only works assuming your opponent uses the Debuff within this skill's Duration.