Deadbolted refers to the locking mechanism on a door that secures it from the inside. The antonyms of deadbolted include unlocked, open, accessible, free, and unsecured. If a door is unlocked, then it is not deadbolted and can be easily accessed. If it is open, then there is no need for a deadbolt. Accessible means that there are no obstacles that hinder entrance into a place. Free refers to something that is not constrained or restricted. Unsecured means that something is not fixed or that it is vulnerable to being opened or tampered with. It is important to know these antonyms so that you can use them correctly in writing and conversation.