clam

be as happy as Larry/a sandboy (British & Australian, American)

to be very happy and to have no worries. We married nine days after we met, and three years on we're happy as Larry. Since he's been at college he's as happy as a clam.

See also: happy

shut up like a clam

to suddenly stop talking and to refuse to say any more. When I asked him about his trip to Korea, he shut up like a clam.

See also: like, shut

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clam up

to refuse to talk or answer. Every time I think he's going to tell me what's bothering him, he just clams up.

Etymology: based on the behavior of a clam (= a sea creature), which quickly closes its shell when something touches it

(as) happy as a clam

very happy. I am happy as a clam living all by myself in this little house by the sea.

Etymology: based on the full form of the phrase happy as a clam in mud at high tide (= a clam that cannot be dug up and eaten, which therefore could be considered happy)

See also: happy