clam up(redirected from clamming up)
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Related to clamming up: clammer
To suddenly stop talking or refuse to speak, typically due to a particular reason. The phrase refers to a clam closing its shell. Naturally, everyone clammed up as soon as the check came. Our usual informant clammed up when he realized there was a mole in the department.
to say nothing. (Closing one's mouth in the way that a clam closes up.) The minute they got him in for questioning, he clammed up. You'll clam up if you know what's good for you.
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]
To refuse to talk or to stop talking suddenly: The politician clammed up when the reporters started to ask about the scandal.
in. to get quiet. (see also dummy up.) The minute they got him inside the cop-shop, he clammed up.