Clam up
Meaning: to suddenly stop talking, usually because you are embarrassed or nervous
Example: The witness was ready to testify at the trial, but at the last minute she clammed up and wouldn’t say a thing. The boy’s parents were sure he knew something about the theft at school, but when they asked him about it, he clammed up.
Example: The witness was ready to testify at the trial, but at the last minute she clammed up and wouldn’t say a thing. The boy’s parents were sure he knew something about the theft at school, but when they asked him about it, he clammed up.
