clam up: meaning, definition, pronunciation and examples
B2Informal
Quick answer
What does “clam up” mean?
To suddenly become silent and refuse to speak, especially when nervous, embarrassed, or unwilling to share information.
Audio
Pronunciation
Definition
Meaning and Definition
To suddenly become silent and refuse to speak, especially when nervous, embarrassed, or unwilling to share information.
To deliberately stop talking or communicating, often as a defensive reaction to pressure, interrogation, or emotional discomfort. The metaphor suggests a shell closing tightly.
Dialectal Variation
British vs American Usage
Differences
No significant difference in meaning or usage. Equally common in both varieties.
Connotations
Slightly more associated with a sullen or uncooperative attitude in British English, while American usage can also emphasize simple shyness or stage fright.
Frequency
Equally frequent in informal contexts in both regions.
Grammar
How to Use “clam up” in a Sentence
[Subject] clams up.[Subject] clams up when/because/if [clause].[Subject] clammed up at the mention of [topic].Vocabulary
Collocations
Examples
Examples of “clam up” in a Sentence
verb
British English
- He always clams up when the topic turns to his family.
- The witness clammed up under cross-examination.
American English
- She clammed up as soon as I asked where she'd been.
- Don't clam up on me now—I need your input!
adverb
British English
- N/A
American English
- N/A
adjective
British English
- N/A
American English
- N/A
Usage
Meaning in Context
Business
Used informally to describe someone who becomes uncommunicative in negotiations or under questioning. 'The CEO clammed up when journalists asked about the merger.'
Academic
Rare in formal writing. May appear in qualitative research descriptions of interview subjects. 'Several participants clammed up when discussing traumatic events.'
Everyday
Common for describing someone who becomes shy, secretive, or unresponsive in conversation. 'He just clams up at parties.'
Technical
Not used in technical registers.
Watch out
Common Mistakes When Using “clam up”
- Using it transitively (e.g., 'He clammed up *her*' – incorrect).
- Using it for permanent muteness (e.g., 'After the accident, he clammed up forever' – unlikely).
- Spelling as 'clamp up' (a related but less common variant).
FAQ
Frequently Asked Questions
The phrase itself is not rude, but it describes behaviour that can be perceived as uncooperative, sullen, or shy.
Rarely. It typically describes an unhelpful or defensive reaction. A positive synonym would be 'discreet' or 'tactfully silent'.
'Shut up' is a direct, often rude command to be quiet. 'Clam up' is descriptive and refers to someone's involuntary or defensive reaction of becoming silent.
Yes, but it's very informal and hyphenated (e.g., 'There was a sudden clam-up when the boss entered'). It's less common than the verb form.
To suddenly become silent and refuse to speak, especially when nervous, embarrassed, or unwilling to share information.
Clam up is usually informal in register.
Clam up: in British English it is pronounced /ˌklæm ˈʌp/, and in American English it is pronounced /ˌklæm ˈʌp/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “As tight as a clam”
- “Close as a clam”
Learning
Memory Aids
Mnemonic
Imagine a CLAM (the shellfish) snapping its shell UP shut. When people 'clam up', they close their mouths as tightly as a clam closes its shell.
Conceptual Metaphor
THE MIND/SPEECH IS A CONTAINER (that can be closed). SILENCE IS A CLOSED SHELL.
Practice
Quiz
In which situation would someone most likely 'clam up'?