A shackle is a metal restraint, usually made of two heavy rings connected by a short chain, used to lock around a person's wrists or ankles to prevent them from moving freely. For most of human history, shackles were used to restrain prisoners or enslaved people. The weight of the metal and the shortness of the chain made it difficult to walk, run, or use your hands normally.

The word also means anything that restricts your freedom or holds you back. A talented musician might feel shackled by a rigid practice schedule that leaves no room for creativity. A student could be shackled by fear of failure, which prevents them from trying new challenges. When you're shackled to something, you're bound to it in a way that limits what you can do.

To shackle someone means to put these restraints on them, either literally with metal chains or figuratively by creating restrictions. When people break free from their shackles, whether real or metaphorical, they're escaping whatever held them back and gaining the freedom to move, think, or act as they choose.