Related Clues:

• Blabbermouth's opposite
• Loud noise lacking in our reticent person
• Tasty sea creature
• Littleneck or cherrystone
• Group inside enjoys terrific shellfish
• Refuse to talk, with 'up'
• Bivalve at a bar
• Burrowing sea mollusk
• One who's tight-lipped
• Oyster's cousin
• Mollusk in a red or white linguine sauce
• Shucking target
• Type of mollusc
• Quiet sort, so to speak
• Metaphorical object of exploitation