clam up

clam ¹  (klm)

n.

1.

a. Any of various usually burrowing marine and freshwater bivalve mollusks of the class Pelecypoda, including members of the genera Venus and Mya, many of which are edible.

b. The soft edible body of such a mollusk.

2. Informal A close-mouthed person, especially one who can keep a secret.

3. Slang A dollar: set me back 75 clams.

intr.v. clammed, clam·ming, clams

To hunt for clams.

Phrasal Verb:

clam up Informal

To refuse to talk.

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[From obsolete clam-shell, shell that clamps, clam, from clam².]

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clammer n.

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clam up

Verb

[clamming, clammed] Informal to keep or become silent

Thesaurus

Verb

1.

clam up - refuse to talk or stop talking; fall silent; "The children shut up when their father approached" be quiet, belt up, button up, keep mum, shut up, dummy up, close up