Related Clues:

• Ruin a surprise
• State secrets
• Squeal, so to speak
• Chatter thoughtlessly
• Tell everyone
• Spill something
• Tell a secret
• Be a squealer
• Have a big mouth
• Ruin the surprise
• Betray a confidence, perhaps
• Yak and yak
• Don't keep to oneself
• Act like 26-Across
• Talk indiscreetly