Lockjaw (noun)

1. A medical condition in which the muscles of the jaw become tightly clenched, making it difficult or impossible to open the mouth.
2. A common name for tetanus, a bacterial infection that can cause muscle stiffness and spasms, including in the jaw.
3. A term used to describe any condition in which the muscles of the jaw are unable to move properly.

Origin:

Early 19th century: from lock 'restrain' + jaw.

Examples:

1. The patient was diagnosed with lockjaw and was unable to open his mouth.
2. The lockjaw was caused by a bacterial infection known as tetanus.
3. The lockjaw was a painful and debilitating condition that made it difficult for the patient to eat and speak.
4. The lockjaw was treated with a course of antibiotics to clear the underlying infection.
5. The lockjaw was a rare but serious condition that required prompt medical attention.