clam up
phr. v..phr. v.. to suddenly stop talking or refuse to say anything, usually because you are nervous, shy, or trying to keep a secret.
phr. v.. to abruptly cease communication or become uncommunicative, typically due to psychological pressure, social anxiety, or a desire for secrecy.
He always clams up when I ask about his family.
The witness clammed up as soon as the police started asking about the night of the robbery.
Despite being normally talkative, the CEO clammed up during the press conference when reporters questioned the company's recent financial losses.
By analogy with a clam closing itself. Compare clamshell (“mouth”), clam (“mouth”).
usually used when someone is being questioned or is in an uncomfortable social situation.
use the image of a clam closing its shell tightly to help students remember the meaning of 'shutting' one's mouth.
He clammed up his mouth.He clammed up.this phrasal verb is intransitive, meaning it does not take a direct object like 'mouth'.