A Hostage

1. A person given as a pledge or security for the performance of the conditions of a treaty or similar agreement, such as to ensure the status of a vassal.
2. A person seized in order to compel another party to act (or refrain from acting) in a certain way, because of the threat of harm to the hostage.
3. Something that constrains one's actions because it is at risk.
4. One who is compelled by something, especially something that poses a threat; one who is not free to choose their own course of action.
5. The condition of being held as security or to compel someone else to act or not act in a particular way.