Related Clues:

• Demonstrate boredom
• Critic’s word for a boring show
• Make a somnolent sound
• [Ho-hum]
• Snooze stentorianly
• Sound from a sleep lab
• Sleep disturbance
• Bother one's bedmate
• Make a little 'night music'
• Sack sound
• Hint to an unexciting speaker
• 'Zzzzzz ...'
• Cause for earplugs
• [How boring!]
• Napper's noise