Shut up like a clam
Shut up like a clam (English) — Silent or laconic / To stop talking and refuse to speak
"Shut up like a clam" in lyrics
To find out who’s American and who’s a low-down Red.
They call them up to Washington to speak for Uncle Sam
But when they ask them what they are, they shut up like a clam
I wish they’d take and put me on the witness stand today
I’d yell so loud old Stalin could hear me all the way