Manacles, also known as handcuffs or shackles, are restraints used to limit the movement of an individual's hands or feet. There are various words that are considered synonymous with manacles, including fetters, binders, cuffs, irons, and chains. These words are often used to describe different types of restraints and their respective functions. For example, fetters are commonly used to restrict the movement of a prisoner's ankles, while irons typically refer to heavier and more durable restraints used in a more permanent confinement. However, the use of any type of manacles should always be handled with caution and only used when necessary for safety and security reasons.