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definitions

clam

1
[klam]
SEE MORE SYNONYMS FOR clam ON THESAURUS.COM

noun

any of various bivalve mollusks, especially certain edible species.Compare quahog, soft-shell clam.
Informal. a secretive or silent person.
clamminess.
Slang. a dollar or the sum of a dollar: I only made 60 clams a week.

verb (used without object), clammed, clam·ming.

to gather or dig clams.

Verb Phrases

clam up, Slang. to refuse to talk or reply; refrain from talking or divulging information: The teacher asked who had thrown the eraser, but the class clammed up.

Origin of clam

1
1585–95; short for clam-shell, i.e., bivalve with a shell that clamps. See clam2, shell
Related formsclam·like, adjectiveclam·mer, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for clam up

satisfy, hush, appease, muzzle, subdue, relax, muffle, assuage, please, soften, soothe, pacify, squelch, mollify, allay, mute, gag, quell, quash, suppress
British Dictionary definitions for clam up

clam up

verb

(intr, adverb) informal to keep or become silent or withhold information

clam

1

noun

any of various burrowing bivalve molluscs of the genera Mya, Venus, etc. Many species, such as the quahog and soft-shell clam, are edible and Tridacna gigas is the largest known bivalve, nearly 1.5 metres long
the edible flesh of such a mollusc
informal a reticent person

verb clams, clamming or clammed

(intr) mainly US to gather clams
See also clam up

Word Origin for clam

C16: from earlier clamshell, that is, shell that clamps; related to Old English clamm fetter, Old High German klamma constriction; see clamp 1

clam

2

verb clams, clamming or clammed

a variant of clem
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for clam up

clam

n.

bivalve mollusk, c.1500, in clam-shell, originally Scottish, apparently a particular use from Middle English clam "pincers, vice, clamp" (late 14c.), from Old English clamm "bond, fetter, grip, grasp," from Proto-Germanic *klam- "to press or squeeze together" (cf. Old High German klamma "cramp, fetter, constriction," German Klamm "a constriction"). If this is right then the original reference is to the shell. Clam-chowder attested from 1822. To be happy as a clam is from 1833, but the earliest uses do not elaborate on the notion behind it, unless it be self-containment.

clam

v.

"to dig for clams," 1630s, American English, from clam (n.). Clam up "be quiet" is 1916, American English, but clam was used in this sense as an interjection mid-14c.

Online Etymology Dictionary, © 2010 Douglas Harper
Idioms and Phrases with clam up

clam up

Refuse to talk or respond, as in Whenever she asks her teenager about his activities, he clams up. This term alludes to the tightly closed valves of a live clam. [Slang; early 1900s]

clam

In addition to the idiom beginning with clam

  • clam up

also see:

  • happy as the day is long (as a clam)
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.