Answer:

CLAM

Answer	Crossword Clue
CLAM	"Happy as a ...."
CLAM	Cherrystone, for one
CLAM	Close-mouthed one

CLAM	Happy mollusk?
CLAM	"B.C." currency unit
CLAM	Bivalve mollusk
CLAM	Close-mouthed type
CLAM	Seafood item
CLAM	Chowder ingredient
CLAM	Nontalkative one
CLAM	Smacker

CLAM	Quahob, e.g.
CLAM	Silent type
CLAM	No talker, he
CLAM	Chowder chunk
CLAM	No blabbermouth
CLAM	Untalkative one
CLAM	Stolid sort
CLAM	Simoleon

CLAM	Uncommunicative sort
CLAM	Happy bivalve?
CLAM	Littleneck, e.g.
CLAM	Buck
CLAM	Epitome of happiness
CLAM	Symbol of happiness
CLAM	Chowder item
CLAM	Happy edible?

CLAM	Shut (up)
CLAM	Chowder bit
CLAM	Hardly a big talker
CLAM	Quahog
CLAM	Casino delicacy?
CLAM	Be silent, with "up"
CLAM	Bit of dough
CLAM	Smackeroo

CLAM	Chowder tidbit
CLAM	Shell occupant
CLAM	Pearl container, perhaps
CLAM	Steamer
CLAM	Closemouthed one

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.