Related Clues:

• Lab greeting
• 'Ruff!'
• Warning from a boxer
• Woofer's output?
• Hidden theme of the puzzle
• Response to "Speak!"
• Fido's tether
• Sandy snippet
• Sound from a kennel
• [This is frustrating!]
• Sound from a junkyard dog
• Remark from Rex
• Sound from a woofer
• Angry dog's sound
• It might mean "I'm hungry!"