Related Clues:

• Make leakproof
• __ of approval
• One of a Navy elite
• Whale's cousin
• Performer with a balancing act
• Mark of approval
• Stamped symbol
• Signet
• Shut up tight
• Circus performer, perhaps
• Affix a kiss?
• Organizational symbol, perhaps
• Close hermetically
• Large seal
• Walrus' cousin