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Definitions

clam up

VERB
button one's lip
Synonyms
WEAK
be silent button up keep one's trap shut not let out a peep say nothing shut up
VERB
quiet
Synonyms
STRONGEST
allay appease assuage hush mollify muffle muzzle pacify please relax satisfy soften soothe squelch subdue
STRONG
ameliorate becalm choke compose console gag gratify ice inactivate lull moderate palliate quieten reconcile settle shush silence slack smooth soft pedal square squash still stroke tranquilize
WEAK
button one's lip calm down can it cool it cool out dummy up fix up hold it down patch things up shut up take the bite out of
Antonyms
STRONGEST
agitate anger annoy depress incite irritate provoke release trouble upset worry
STRONG
aggravate disagree disturb excite move
WEAK
turn up
VERB
quieten
Synonyms
STRONG
clam dampen deaden dull extinguish gag hush lull muffle mute muzzle overawe quash quell quiet shush soft pedal squelch stifle still subdue suppress tongue-tie
WEAK
choke off close up cool it cut off cut short decrease the volume dry up dumb dummy up hold one's tongue hush one's mouth hush-hush keep it down pipe down quiet down say nothing shut up sit on strike dumb
Antonyms
STRONG
agitate allow disturb encourage help irritate let go release start
VERB
shush
Synonyms
STRONG
clam dampen deaden dull extinguish gag hush lull muffle mute muzzle overawe quash quell quiet quieten soft pedal squelch stifle still subdue suppress tongue-tie
WEAK
choke off close up cool it cut off cut short decrease the volume dry up dumb dummy up hold one's tongue hush one's mouth hush-hush keep it down pipe down quiet down say nothing shut up sit on strike dumb
Antonyms
STRONG
agitate allow disturb encourage help irritate let go release start
VERB
silence
Synonyms
STRONGEST
cut off gag muffle mute muzzle quash quell squelch stifle subdue suppress
STRONG
clam dampen deaden dull extinguish hush lull overawe quiet quieten shush soft pedal still tongue-tie
WEAK
choke off close up cool it cut short decrease the volume dry up dumb dummy up hold one's tongue hush one's mouth hush-hush keep it down pipe down quiet down say nothing shut up sit on strike dumb
Antonyms
STRONGEST
allow encourage help let go permit release start
WEAK
be noisy communicate talk
VERB
stifle
Synonyms
STRONGEST
curb muzzle repress silence smother squelch strangle suffocate suppress
STRONG
asphyxiate burke check choke constipate cork extinguish gag hush kill muffle spike squash stagnate stop stultify torpedo trammel
WEAK
black out bring to screeching halt choke back clamp down cover up crack down dry up hold it down hush up put the lid on shut up sit on
Antonyms
STRONGEST
allow encourage free let go loose release
STRONG
aid assist bear begin create help start
WEAK
persuade
VERB
withhold
Synonyms
STRONGEST
conceal deduct deny detain hide keep refuse resist retain suppress
STRONG
abstain bridle check constrain curb disallow hold inhibit kill refrain repress reserve restrain spike
WEAK
dummy up hold back hold down hold out hold out on keep secret keep to oneself keep under one's hat keep under wraps sit on stop oneself
Antonyms
STRONGEST
allow disclose divulge expose free go along grant lay bare let go let out open release reveal show tell uncover
STRONG
aid assist help indulge liberate permit use

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The question prompts Epstein to clam up: “Send me a number to call I don’t like records of these conversations.”

From The Wall Street Journal • Feb. 12, 2026

JPMorgan said an important part of its more positive view on European CRE was the willingness of European banks to continue providing finance to the sector as wholesale funding markets have started to clam up.

From Reuters • Mar. 28, 2023

I especially liked Chase Sui Wonders as David’s passive girlfriend, Emma, who tends to clam up and shut down in ways that are more humanly recognizable than the others’ queen-bee diatribes.

From Los Angeles Times • Aug. 4, 2022

On a normal, micro, day-to-day, typical-conversation level, please don't clam up.

From Washington Post • Sep. 6, 2021

“Superstitious folk don’t like to talk about things they’re afraid of. He was about to clam up, and I needed to know what he’d seen in the forest.”

From "The Name of the Wind" by Patrick Rothfuss