Related Clues:

• Shellfish
• One disinclined to talk
• Bisque morsel, perhaps
• Source of an advantage, figuratively
• Uncommunicative one
• Quahog
• Digger's find
• Bivalve mollusk
• Rock-clinging mollusk
• Mixed seafood item
• Type of mollusk
• Raw-bar selection
• Good secret-keeper
• Place for steamers
• Chowder mollusk