Related Clues:

• Night sound
• Nocturnal sound
• Sty sound
• Midnight rumble
• Indicator of indignation
• Audible inhalation
• Nocturnal annoyance, perhaps
• Sound caused by the soft palate's vibration
• Sound made while sacked out
• Starting-gate sound
• Keep others awake at night, maybe
• Keep your bedmate up, maybe
• Cause of a rude awakening?
• Nap noise
• Something boring