Related Clues:

• One causing ennui
• Drill holes
• Make weary by being dull
• Yawn producer, perhaps
• Fall in drops
• Make weary
• Insomniac irritant
• Yawn-inducing speaker, e.g.
• Faucet annoyance
• Dull person
• Tidal flood
• One who's easier to pray for than to visit, according to C. S. Lewis
• Ho-hum sort
• Make a tunnel
• Water fall?