Definition
to suddenly become silent, often due to embarrassment, nervousness, or reluctance to discuss a certain topic.
（因尷尬或緊張等）閉口不言，沉默
She clammed up when asked about the sensitive issue.
當被問及敏感問題時，她突然沉默不語。
Everyone was engaged at first during the discussion, but eventually, they all clammed up.
一開始討論時每個人都很投入，但最後他們都沉默不語了。
He clammed up as soon as he heard her question, clearly not wanting to talk about it any further.
他一聽到她的問題就沉默不語，顯然不想再談下去。