Lock-jaw is a term that refers to a medical condition that affects the jaw muscles, causing them to become stiff and difficult to move. This condition is most commonly associated with tetanus, but it can also be caused by other factors such as trauma or infection. Although lock-jaw is the most commonly used term, there are several synonyms that can be used to describe this condition. Some of these include trismus, tetanic spasm of the jaw, jaw spasm, jaw rigidity, and tonic spasm of the jaw. Each of these terms is often used interchangeably to describe the same condition.