Things in action are items of property to which a person is legally entitled either because the items are owed in a debt or because the person has another legal claim on them. Things in action are often the subject of tort lawsuits. They can involve sums of money, vehicles, houses, etc.
Once the court makes a final ruling on the items of property in dispute, they are no longer in action. They will either be awarded to a party or not. Things in action can also cease to be in action if the period during which they can be sued for ends. For example, a creditor may only be able to sue a debtor for things in action for five years. So, if five years passes without a lawsuit, then the money that is owed to the creditor would no longer be in action.