Related Clues:

• Get in trouble, in a way, with 'on'
• Squeal, so to speak
• Chatter thoughtlessly
• Tell everyone
• Spill something
• Tell (on)
• Tell a secret
• Rat, so to speak
• Be a squealer
• Have a big mouth
• Ruin the surprise
• Give away a secret
• Rat someone out
• Betray a confidence, perhaps
• Be a rat fink