Possible Clues:

• Type of chowder
• Steamer, e.g.
• Tight-lipped one
• Mollusk in jaecheop-guk
• Seafood in a shell
• Stop talking, with ''up''
• Chowder thingie
• Mollusc left in river
• It's one-fifty in the morning, so shut up
• No blabbermouth